Everything has been fine on my T2 for nearly 3 years with a good picture and last Thursday I notice picture break up and some channels saying signal is too weak. I live in East Yorkshire and my strongest transmitter is Belmont. I moved here from Leeds using Emley Moor transmitter just over a year ago but I have not had any problems since moving here with a good signal from Belmont.

After checking my old 9200 which is still working and tuned to Belmont I found I was picking up another weaker transmitter on the T2. I think it was one for East Anglia So I did a default reset and auto tune without aerial connected and then manual re tune back to the Belmont transmitter and its OK now. ( An auto re tune with aerial connect still picked up the weaker transmitter)

My warranty expires in March and Im wondering if this is going to happen again while Im away on holiday next month. Any ideas what could be the fault and has this happed before to anyone ?

Very strange.
There has been some thick fog recently, this contributes to atmospheric conditions which affects the propogation of TV signals.
In this instance, I wonder if the T2 was retuned during such conditions, that it found (maybe Tacolnston) to be receivable whilst Belmont was not, and when the conditions reverted to normal is the problem you opened with.

The moral is, don't try to retune DTV equipment during atmospheric conditions unless you are prepared for the consequences (not that that necessarily applies here).
Rather use the onscreen signal meter (available in the manual tuning menu) to determine the true state of affairs.

I only re tuned after I could not pick up most stations and not in fog. Has anyone ever had there T2 forget which transmitter it is tuned to ?