falcon ferolli 11 combi boiler pressure in, no pressure coming out?

Wouldn't recommend tackling the heat echanger.That usually involves going into the combustion chamber and thats gas /corgi only.
Before you go for bigger problems there are other things to check. Is the cold water all over the house still good pressure?
If yes the boiler cold inlet feed pipe may have a filter in it ( most do). Not too easy to get at on this model but you should be ok if he managed to repair a mains leak..

T.h.s
May 2007