Right, basically, I've been learning guitar for a while now.

Started grade 7 pieces last year, and have only got list A and B, no C. (Been going slowly and took a break because of GCSEs)

Was going to get started on C after Summer and then take grade 7 next March or so

But I've just discovered that the guitar syllabus is changing next year for 2009.

Therefore, does that mean, that all the pieces I've learnt from the old syllabus, cannot be used in the new syllabus?

Because if so it means it's just been a complete waste of my time...the only piece I'm doing which features on the new syllabus as well is the Menuet, but then I'll have to learn number 1 as well as 2.

Help anyone?

The old pieces can be used for the first exam session of the new syllabus, but supporting tests must be done from the new syllabus.
All the pieces have to come from one syllabus, you can't mix across the two.

If you take the exam in Nov/Dec: old pieces; old supporting tests
If you take it in Feb/Mar: old or new pieces; new supporting tests
If you take it in June/July: new pieces; new supporting tests

I checked the ABRSM website though, and on the page about overlap periods it says nothing about guitar, which I took to mean that I couldn't use the old syllabus in 2009.

So I'm alright if I go for Feb/March with old pieces, just new supporting tests?

Even if you can't use the pieces you have learnt, it has NOT been a waste of time. You will have benefitted from learning those pieces and all the technical challenges that go with them.

I think it is a bad idea to learn only 3 pieces for exams. Surely, you want a bigger repertoire and wider experience than that?

Learning any music can only make you into a better musican.

I agree completely! However, since you seem to have put the work in for Grade 7, would you consider working on grade 7/8 pieces until March (not doing the grade 7 exam) and then working on grade 8? It's only an idea: I think that you'll be fine with the pieces you have for March if not!