You can still get axles for Romford/Markits wheels to suit the old Triang-Hornby chassis. IIRC they're 9/64" diameter. There's both plain ones & knurled ones for mounting the gear wheel. Dave Cleal at Mainly Trains (usual disclaimer) stocks them, & he also does suitable replacement coupling rods, as I recall.
I suspect this was a way of getting the layout sold without incurring large eBay fees, via 'private arrangement'. I too wonder if there will be any followup.
Surprisingly not. However, it seems to be the only railway item on offer by the vendor. Of course he may have got his inspiration for the price from our friend...
Nice job, West_riding. You know, that loco wasn't really a bad piece of work for RTR when it first came out, was it? Pity about the 'orrible solid wheels, of course...