Hi, got a customer with an old TSO boiler(20-25), it has a selectos D42 burner and is in need of replacement, however as budgets are tight I suggested that instead of replacing the whole thing maybe a replacement burner would be a cheaper short term option. I read on here from one of you more knowledgable types that there was a burner that would "fit the slot" so to speak - however this was a while ago and can't find the post where I read it. Please could anyone remind me of which burner that might have been that will fit this old boiler ?