Thank you everyone for your advice. The two engines mentioned have been sold, now I need to sell the two half finished 2" Fowler Superba ploughing engines, the remainder of my work. They were being built to exhibition standard, from original drawings, but could be finished to John Haining's design with just a little adaptation. But they are big projects, although now within reach of a 3 1/2" lathe: all the large stuff is done.
Looks like boiler certs are a now a nightmare, but these engines pre-date the 2001 CE marking requirement, so a hydraulic test is sufficient. They were tested and certified at the time of building, but the paperwork is proving elusive to find :(