Well it seems that a fuse had blown. Apparently these programmers are connected to another box that houses a 1.5amp fuse. Replacing the fuse fixed the problem but the engineer fitted a new programmer anyway.
I am now waiting for him to come back and replace the so called "much better"...
We had a new boiler fitted about six weeks ago and they replaced our old progammer with a Honeywell ST9400C programmer.
From day one we noticed that the digital clock was gaining a few minutes a day and phoned the company who installed it who kept promising to get back to us, but haven't...