Baxi 105e. Central Heating working, no hot water through taps !?

Hi everyone. I've got a 3 year old Baxi Combi 105e, that, for some reason last night, got low water pressure and turned itself off. I turned the left dial to reset it and the Power LED goes Green. After 10 seconds or so, the CH fires up and that LED goes green. The burner on LED turns yellow, meaning everything is OK. However, the Domestic Water LED does not come on. When I turn a tap on, the Burner LED normally turns green and the hot water comes through. But nothing !! The only way I've managed to get the DW LED to come on, is if I turn off the Central Heating system, making the boiler try to fire up the HW. The light flashes for about 5 seconds, then nothing !! Any ideas guys ??

Thanks for your help.

Paul