Hi guys after months of deciding finally my repertoire for next year's DipABRSM Piano Performance is set ><

Bach's Toccata in E minor
Mozart's Sonata in Bb major K570
Brahms's Intermezzo in A Op118 No2
Debussy's La cathedrale engloutie

Any advice please?

I assume that they are all on the repertoire list and that the timings are OK (allowing for breaks between and for the fact that you probably won't play at the same tempo as your favourite recording). On that understanding (I haven't checked):

I like this programme. It's not all that adventurous but having the Bach Toccata rather than a P&F is slightly off the mainline and besides, my penchant for taking the road less travelled may not be shared by your examiner nor reflected in the marks you may get therefore! Only 4 composers is good in terms of program notes. The key sequence doesn't flow but this matters a lot less for piano than it would for voice, for example. Good range of styles and periods. Shows off a range of technique. I don't know if the programme plays to your strengths but if you can play it and make it work for you, go for it. Good luck!

I agree with Robodoc, fairly straightforward and safe repertoire, but shouldn't be too difficult to learn, the Mozart K570 is hardly Dip standard, there's only a couple of tricky bars (twice) in the first movement.
The other pieces are pretty well known, I wouldnt worry about doing the Toccata instead of a P & F, its a good bit longer than a P & F would be so balances the timings better between the four pieces. I gues sth Brahms is the shortest. When you hear recordings of the Debussy by eminent pianists, you'll find quite a variety of interpretations, so listen to a few, and model you performance on the one you like.

I agree with fsharpminor about the Debussy interpretations. You should really listen to Michelangelli's (spelling?) recordings of them on Youtube. I believe he has all of them on Youtube. Good program selection too.

This may be of interest to you in terms of Debussy:

http://www.youtube.com/watch?v=rfSBddhFvyA

I don't really like some passages of Michelangeli's interpretation of this particular prelude. It's just my opinion, but I think some passages are too fast, some too slow (he plays bars 5-13 as they're written whereas it's generally accepted that bars written in 3.2 are doubled in tempo). It's a highly atmospheric prelude and when I listen to Michelangeli's interpretation, I'm never drawn in from the beginning. I feel a bit guilty about saying that, but it's just my opinion.

It's important to listen to other recordings, but remember, you don't need to 'model' your interpretation on anyone elses.

In terms of contrast of different musical styles, your programme is quite balanced.

But make sure that the Mozart and Brahms's pieces should be more well-prepared since the examiner may concentrate on your performance quality in these pieces.