Ours is a Worcester one, (part of Bosch group) and apparently is called the "rolls-royce of boilers! since we moved in here in 2004, we've had continual problems with it. Now whether that's just how combi- boilers are, I don't know, but our old house had a standard system and it worked a treat!
We have a glow worm Combi fitted in 2003 (I think now part of the same group) in the first 5 years the bits I have seen replaced are
1 circut board
1 new interface panel
2 new heat exchangers (I managed to keep one of these)
2 filling loops
2 diverter valves
1 sani block
I asked the engineer if it would be better to get it changed?
His reply was its had that many new parts it is virtually new and a new one won't last any longer
The 25+ year old back boiler it replaced we had for 5 years and never needed any parts other than a service until it finally gave up and we couldn't get it fixed due to its age.
We consume thae same amount of gas as we did before so so much for the savings
I fitted a magnaclean and a strainer on the return loop and since then its just needed a water sensor which packed up over the xmas break so just a few days with no hot water from the boiler. The heat exchanger gets swapped over every 6 months and I get it cleaned out at work.
The dirt that first came out of the magnaclean had to be seen to be believed.