I started playing in March, being taught by my wife who is grade 5.
I thought I'd see whether I could get through a couple of grades before seeking professional lessons, does anyone have any thoughts on this ?

I started teaching AP a few years ago, being grade 8 at the time myself. I think I've done more good than harm (*cough* straight distinctions *cough* ). Seriously, I think to see whether the piano is 'for you' you could learn for a while with your wife before deciding whether to pay for a professional teacher. It could be that being taught by your wife may or may not work in practice in the long run: drawing a parallel, some people teach their own children; others find it doesn't work as they cannot make the transition from parent to teacher. But I'd say there's no harm in trying.

Incidentally, is she still learning to play the piano herself?

She's just getting back into regular practise at the moment, we had a long period without a piano.
The approach you mentioned above is what I'm doing, I thought I'd give it a couple of years and then maybe get both of us prof lessons. I'm doing grade 1 in the next session so I'll see how that goes.

I suppose it all depends on what your aiming for and what you hope to achieve. If you want to learn as a hobby and just for your own pleasure then how you go about it is your own personal choice. After all, you'll only have yourselves to judge each other in the end. Having said that, you will probably still reach a point down the line where you will need help with your technique etc to progress further. If on the other hand you are hoping to play professionally and/or become an exceptional Pianist then you need the best teacher that you can find!!
Good luck with whatever you decide.

Gae

My son has been taught up till now by someone who has only gone up to grade 6 herself. She passes students on after grade 4. I really couldn't advise on whether or not her lack of experience has done any harm to his technique, but he has developed an enthusiasm for music, scored a good distinction on his grade 3 last term and won an award giving him free piano lessons at his senior school. I guess what I'm saying is it doesn't seem to have done any harm. I think that ability to teach is probably more important than overall musical ability (within reason) at the lower grades. We've just found out my son's new teacher is a concert pianist, so he will be going from one extreme to the other! It will be interesting to see the difference.

The problem that may arise from a teacher who is a good musician but inexperienced on the technique of the instrument is that the pupil may acquire a technique with a fundamental flaw in it. Of course, that can arise over a range of levels, and the technique of some instruments is easier to teach than others. Easiest are strings and piano, because bad technique is usually visible; most difficult is voice because you can see rather little and must diagnose problems largely by ear.* Brass and woodwind are intermediate in difficulty, because some important aspects of technique are out of sight inside the mouth, but it is easier to get a wind player than a singer to describe what is going on (e.g. whether tounguing is happening on lips, teeth or hard palate, each of which a horn player needs in the appropriate register).

Best for an inexperienced teacher is to confide in his/her own teacher and get advice when problems appear to have arisen with the pupil.

* I have never sung seriously myself, but I have been around serious amateur and student singers and I have heard voices deteriorate under the guidance of one teacher and blossom with another.

Well I've bitten the bullet and I'm seeing a professional piano teacher tomorrow.

I'm having to tread very carefully though, I don't want my wife to think her teaching of me was bad.

Based on my experience, I’d say that anyone could learn to play a musical instrument, at any time in life.
My children both played the violin using the Suzuki Method (with a proper teacher) when they were 3 and 4. I was in my mid 40s at the time, but I discovered that what they were learning, I was too! (I had no musical experience prior to this!) My wife bought me a full-size violin and I progressed up to Book 3, when I began to develop arthritis in my fingers and couldn’t close the fingerboard.
I gave up then, but always hankered after the pleasure of learning an instrument.
Cut to last year (I’m now 66) and I took the plunge and bought a keyboard (and headphones!), Suzuki piano book one and the tape which accompanies it.
I began playing in July last year and found to my astonishment that I was able to learn a new tune each month – I’m currently learning number 15 (out of 18) and I expect to graduate to book 2 at Christmas time. I have a young friend who teaches the piano and he comes by once a month or less frequently and puts me straight if he needs to. But basically I’m teaching myself.
The method requires you listen (daily) to the tape of the music you will be learning in the future and it is a step by step, painless way of learning to play a piano or keyboard. I intend to take piano exams, but I won’t start with grade one until I’m grade two standard – by then it should be duck soup!
I’m sending the tape and Book one to my son in Cyprus so that he can teach my 3-year-old granddaughter to play.

There are many advantages to this method:
From the very first (Twinkle) you are playing tunes
There are no scales or arpeggios, all these are integral to the music
Each tune introduces one or more new techniques
You don’t move on to a new tune until you’ve mastered the last one
You should continue to practice all the ‘old tunes’, since by so doing you are practicing all the techniques you’ve learned
You build up a repertoire – I’m well pleased that I can rattle off all these tunes
And above all, it’s fun!
A word about reading music: Suzuki students don’t generally learn to read until about book three or four (there are 10 altogether, I think). By then they are really proficient and it comes easily to them. So in the early days, the written music doesn’t get in the way of playing

One of my motives for learning the piano is so that I can accompany my grandchildren on whatever instrument they decide to take up. But I also get a huge kick out of learning a new piece.
I just sat down last night and played through my repertoire after not playing for a month (holidays, etc). I only made one or two mistakes in each piece.
I probably won't know how good I am until I submit myself for that first grading. Only then will I know whether my way of learning is valid or not. In the meantime, I'm having a ball!
And (if you have a piano or keyboard) it costs next to nothing – £10 for the Book One music and Books One and Two cassette).