No HETAS certificate for long burner installed in 2015

[someonelse]

...The general builder fitted it and was told by The then owner that he'd get someone to inspect it and get it certificated. This never happened.

Who should be held responsible for this?
It's far too late to be worrying about who was responsible.

...We duly booked an inspection by a HETAS engineer
Why? If the buyers wanted an inspection, they should have arranged this themselves. Not down toyou. However, water under the bridge now....

to find that several things need doing, although the log burner itself passed the safe operating criteria.
So what 'needs doing'?
If the burner passed as safe, I would ignore everything else. The buyers can take whatever remedil action they feel they want todoonce they are the owners.

What do we do now!!!!
Advise your buyers that the burner is safe as per the inspection and that therefore you see no reason to delay Exchange of Contracts.
We should be moving in 20 days!!!

No reason not to move in 20 days (assuming everything else is in hand)

 

[dilalio]

Call the buyers' bluff... They're also presumably keen to move into their new home and are being worried by their conveyancing solicitors!

Or... If this is a concern to both parties, then do a deal and split the costs of any such repairs down the middle... You've enjoyed a number of years in the property, without having to shell out for work on this installation so, may be worth a contribution as part of a goodwill gesture.

I wouldn't go into full panic mode... All depends on the traits of the people involved.