The price seems reasonable, but you're not in a standard position. Your 20 hours technically mean that you only need another 25, but almost certainly you'll need more than that but probably less than another 45.
I'd suggest that this school seems not too badly priced, but you'd be far better of paying "as you go", rather than signing up to a fixed price deal which some might benefit from but probably you won't.
I have to say however that any school which charges landing fees for it's own aircraft is artificially hiking the prices up a bit. at perhaps 8 circuits an hour - and of-course you'll be doing oodles of them, this can add up !
G