GLowworm Ultimate 60FF - the heating works but the hot water does not?

I have a Glow Worm Ultimate 60FF, the hot water system is not heating the water however the central heating works fine. I have made comparisons and between the central heating and the hot water systems at various points and the Honeywell control unit appears to be working fine, passing the "call for hot water" signal (as is the heating) but it does not light the boiler. Just wanted to see if any one had a clue before I buy a new boiler control panel.