Went off to see Yarwood expecting to see all the portholes in place and quickly noticed (I'm observant) that they weren’t. It seems something was lost in translation between Procast, Barnowl and Lambon and the two smaller back cabin porthole apertures in the cabin sides were 5mm too small. This entailed a lot of fiddly grinding to put things right. The problem with these ports is that even when the aperture is correct, the holes for the fixing screws have to be tapped at the very edge of the cut-out, so care had to be taken to ensure the holes did not become too large. On the positive side it would have been more of a problem if the holes were 5mm too large.
The calorifier - sounds like a Victorian device:
"Grimwolds patentented Calorifier provides copious volumes of hot water on tap"
It is, in my opinion, just an unvented hot water cylinder. Try going into B&Q and asking if they have any calorifiers. No doubt someone will correct me in due course.
Anyhoo the said item is in place but not yet plumbed in.