C&M Britony Combi Boiler HELP PLEASE

Hi

Over the last few weeks the water temp has not been very hot at all when showering or even running the kitchen tap. Strangely quite often the water from the bathroom tap can be very hot and lulls you into a false sense of security before you jump in the shower!
The boiler fires up and the orange light comes on when there is a demand so it recognises that its supposed to be doing something.

To make matters worse last night it decided to continually go into lock down and I had to reset every 15 mins or so. This was not with any demand for hot water it was just with the central heating.
Can anyone help please.
Many thanks
Tash

is it a 24kw model?
does it have separate controls for ch and dhw?
has this started all of a sudden?

check thermista??? does ch work ok??? 3 way valves are prone to sticking also on this model.

depending on which model of britony if its the all white version they are prone to pcb. if you say the lock down as in the red light with the no flame symbol as long as its the all white version i would say its more than likely the pcb for that problem