he wants to do the work to your property but does not want to end up with the burdon of having a at risk gas installation on his hands. a few checks would see what work needs done.
The main thing to check would be the appliance working pressure. If the pressure is 20mbar then its working at designed pressure and no one could really kick up too big a stink. If not its undersized pipework and will 100% need renewed
iain
October 2008