Setting the CH & HW timer on a Potterton EP 3000?

We have just moved into a new flat and both the central heating & hot water are working fine. The Potterton EP 3000 is the model in the kitchen used for setting the CH & HW.

I've followed Mike Partington's advice and set the day and on & off times for both the central heating & hot water (both CH & HW were set to twice and the main switch was set to Auto). Unfortunately, despite all this it has re-set back to it's default timing overnight.

We need to set the timer on a Potterton EP 3000 so that the central heating comes on at 05.30 (on 1) and off at 08.00 (off 1) and then come back on at 17.30 (on 2) and off at 21.30 (off 2). We also may need hot water for 2 showers between 6-8am and then 18.30-21.30.

Please can someone help and tell me what I'm doing wrong????