Bargaining the right price for rent to buy

Hi, I havnt been here in a while now, but I have just viewed a property in Celbridge on the rent to buy scheme, however the asking price is 375K. Its a 3 bedroom semi detatched house, as we really dont want an apartment if we are going to end up buying, we'd see ourselves staying here for years, even if we started a family. We did not sit to to thrash out numbers with the guy or anything, but is there room for negotiation with this scheme? if we have to rent for 2 years than what would a realistic price to offer be? Also, I spoke to a Mortgage adivsor today before meeting the developer and he said in theory my partner and I would only be approved for a mortgage of 305K 'in principal' as of today and our circumstances. We would also have to pay a deposit of 10k which we could loose at the end of the agreement should house prices fall dramatically along with the 'rent'. Look I'd appreciate any advice. Thank you.