Very slow progress alas - I was sent a copy of the instructions and have made some progress on the 517 but I need to make a new bunker given my decision to go for an open cab & round top firebox version. As my workshop is still packed away, I haven't even started on this even though it's fairly straightforward. However, the news that Mrs CKPR-to-be has decided that we need a new dining table means that I might now get access to the old and rather battered pine kitchen table for a spot of sawing, filing and soldering of the old nickel silver sheet !
As for building the Mallard 517, I've found it to be quite straightforward with the only awkward step being the very thin overlays - they were a bit of a pig to solder on but do look very nice once in place. and after some post-soldering cleaning up with a fibreglass pencil.