Hello I am a solicitor with 20 years experience. I will try to help you with this.
This is a contract dispute and the answer will be in the documentation you signed at the time you took out the mortgage.
You need to look at correspondence from the conveyancers (whose fees were very low if they only charged £175) and the mortgage contract to see what terms apply at the end of the 2 year period. I fear that the charges you have faced though may well be allowed under the contract.