On the last two ovens I've owned (neither Bellings) - I used to cycle the power off and on again so that the clock flashed - then depress and hold in two buttons (number 2 & 3 from the left) and use the plus and minus buttons on the right to set the time.
Any time would do - the oven had no idea of the correct time - and then I could operate the oven normally - God knows why they put timers on ovens - more trouble than useful and another point of failure - quite unnecessary.
I hope it works for you...
Good luck...
Peccavi, July 2013
