Calydra 100 Timer problem?

I have a C&M Calydra 100. It's working fine on all modes, except when it is switched to Timer mode the timer turns round and makes a "click" noise when the selected time turns round on the dial, but the boiler doesn't fire up.
I recently paid BG to come and fix the boiler because it wasn't firing up at all, and it was a simple loose wire (£127 for that, i nearly cried) - could this be a similar issue but just a different wire? I live on my own so don't have anyone who could have a look at it for me, so I would really appreciate any help as if it's something simple I'll try to do it myself rather than pay again. Many thanks in advance