Hello Alan, I stumbled across your post on the going rate for straight boiler swaps in the London area. I'm new to the CC so forgive me if this is the incorrect method of contacting you but i couldn't see an email address anywhere. I was wondering if you went ahead with recommending installers as this is something I may be interested in helping you out with. for what its worth I would say £250-£300 would be acceptable considering travel expenses and the use of consumable materials plus the odd fitting here and there that has been left off the materials order. My email address is niall.evans@live.co.uk if your interested in responding, cheers, Niall.