A timely reminder that there are no substitutes for patience and careful attention to detail. The info in your blog, and in the video which you provide a link for, has all been very useful. Thank you. I've faffed about trying to build crossheads and slide bars for the Hornby chassis out of stray bits of brass sheet and wire. The results have been pretty ramshackle. This has given me the impetus to try again. Thankfully there seems to be an infinite supply of second hand Hornby chassis out there.