Thanks for the kind comments folks, much appreciated. Cultra is Saturday 12th November and it will be a real privilege to bring the layout over the water. Have visited the Museum before on one of several trips to Ireland & it is very much a favourite. Bit of a trek to get there though, as I'm based in SE England...
Doing the layout to 36.75mm gauge was a lot easier than might first seem. Plain track is hand made, using code 100 FB rail [to simulate the lightweight stuff used on the SLNCR], while the points were commissioned from Marcway of Sheffield. 50% more than Peco, but they are self isolating, so wire in tube is all that is needed for operation. Fine scale standards work well in the broad gauge, so there is no need to go for S7, unless precision is your thing. Slater's do a broad gauge loco axle, while their wagon and coach axles are long enough to tweak the wheels out to 34mm back to back [33.98 to be precise, but I'm not!]. The rest is no different to any other type of modelling - except you will not find anything ready to run!
However, the Alphagraphix catalogue contains a wealth of stuff to get you started. Their Tyrconnel range contains an increasing number of steam outline locos and etched brass coach kits. Indeed, it is possible to model the Timoleague & Courtmacsherry Tramway fairly easily, as most of the steam locos and coaches are already available. They have a lot of card kits too & at £3-4 each are cheap enough to use as colour plans for scratch building bodies in plastic sheet and strip, though they can be made into perfectly nice models as they are. White metal under frame detail is available too.
So, in many ways, no excuses for getting the gauge right & nothing sets the Irish scene better in my opinion. Yet, as far as I can tell, apart from the legendary Castle Rackrent, by Richard Chown, there are no other 7mm scale broad gauge layouts being exhibited. Indeed, at the moment, it seems there is one P4 [Valentia Harbour], one 3mm [Ballyconnel Road] and maybe one S gauge line & that is it. Plus Adavoyle, of course. I'd love to be proved wrong!
By the by, Sir Henry's chassis occupied a disproportionate amount of my time on Sunday as, after painting the frames, I tried to re-assemble it. It would have taken a lot less time if I'd noted the order in which I'd taken it apart. However, have since had more practice as it needed a fair bit of fettling to get rid of paint which had got into the slide bars, but happily, all is running smoothly again. Indeed, the boiler/smokebox and tank/cab units have been reunited again, after priming and a spray of Halfords matt black. While this covers well in my experience, it is far too dense a colour, so the loco now needs time to high highlights, weathering etc before its next photoshoot.