Hi There,
You have to be a FTB (although I believe there may be one or two exceptions - widowed etc..don't quote me though...)
In terms of the clawback, if, using the figures you suggest, you sell in two years you will owe 33.3 % clawback....same if you sell in year four, eight or nine....after year ten, that 33.3 will drop by 3.33 precent every year til year twenty - if after that time, you sell - you incur no clawback...
A few other rules etc:
You cannot rent out an AH.
You cannot change lender with AH.
You will ALMOST CERTAINLY be done on the valuation...ie you will end up paying more clawback than you got discounted in the first place!!!!
Hope that helps!