hi starrs everything you were told by gasman is spot on,and the flue cannot be passed as satisfactory without a visual check with a torch and then lighting a smoke pellet
. you need to remove the fire to lean into the chimney breast to look upwards.the white panels the man removed are the elements that sit above the burner rail at or near the front of the fire
also it does not matter that the landlord is corgi registered, it is the man/woman doing the work and signing the certificate that needs to be registered
you need to br ready for a possible disagreement with the landlord/fitter because you will claim that they have not done something they have signed to say that they have.
the chimney breast area should be clean if they removed the fire, should,nt it?
if they prove awkward mention CORGI, (www.trustcorgi.com) good luck