I'm not a tradesman but the regulations seem clear:
Do you have to have a condensing boiler?
No. You should have a condensing boiler fitted if it is reasonable to do so
http://www.direct.gov.uk/en/HomeAndCommunity/Planning/BuildingRegulations/DG_10030520
So what I don't understand is, if a new kitchen has to be demolished to fit a condensate pipe to an appropriate indoor waste, then why don't you (the installer) exercise your right to stipulate that the condensing requirement is "unreasonable" and fit a non-condensing type. Unless there is an inspector involved, I can't see that you have to justify your decision to anyone other than the customer.
Do you have to have a condensing boiler?
No. You should have a condensing boiler fitted if it is reasonable to do so
http://www.direct.gov.uk/en/HomeAndCommunity/Planning/BuildingRegulations/DG_10030520
So what I don't understand is, if a new kitchen has to be demolished to fit a condensate pipe to an appropriate indoor waste, then why don't you (the installer) exercise your right to stipulate that the condensing requirement is "unreasonable" and fit a non-condensing type. Unless there is an inspector involved, I can't see that you have to justify your decision to anyone other than the customer.