I presume you got the site free of charge. Of course that is great for you in lots of ways, but you possibly have no record of putting money aside on a regular basis. The absence of a savings record is a a bit of a disadvantage: it's harder to prove to the bank that you have the capacity and the habits that enable you to make repayments on a mortgage.
You're not dead in the water, though. It's certainly worth discussing it with the bank.