I had a WB 28i junior for 17 years.
It worked fine although I added 5 radiators to the system in that time and an extra shower room.
Few problems were fixed under warranty: 1. fan when I mistakenly turned it off for a month.
2. Heat exchanger which got clogged possibly because there was no filter installed and I cleaned the system with x400.
3. Expansion vessel kept on deflating and needed top up every couple of weeks, but lasted until the end.
4. Analogue timer which I paid for, bought from
screwfix and had it fitted by service engineer .
5. Diverter valve x 2, somehow this caused many problems in the last 2 years.
Eventually, as I was repiping the whole system and replacing all radiators, I decided to go for a new more powerful boiler and never looked back.
I get better flow in the loft conversion and we can use 2 showers simultaneously.
Heating is very efficient, but it was expected considering that it's all new and there are no more dead legs anywhere.