Hi Jack, there are 6 lenders now offering 100% FTB mortgage's, of these FA, PTSB and UB require evidence of 3 years continuous employment, and they will ask for 3 years P60 to confirm this, BOI, ICS and EBS only require 1 years continuous employment, so iIsuppose it depends who you have applied to... if its a lender who requires three years continuous employment then It may be difficult to get around, however if its a lender who only requires 12 months continuous employment then you may be ok given that you have been banking with them for 12 months.
good luck with it,