A company about two miles from me has got the solar work and have been asked to quote for the heating.their man is going to commision the houses when complete.We pressure test after first fix so if any problems later cn can only be due to follow on work by other trades.i have stipulated that i will not be returning for any works that were not in the original contract unless a suitable fee is agreed.The company partners want me to do the work due to local reputation.