Jamie,
Thanks, good advice!
pH,
Thanks - that's very helpful and what I wanted to assume, I think, but you have expressed it clearly enough for me make a decision! Photo evidence seems to be similar for 44687 as 44686, but nothing clear out there from late 61 to early 63.
Simon,
Thanks for your kind comments. I'm no expert so I'm sure you can do yours justice. If you're using the Crownline kit and a modern Black Five as the basis, I'd be more than happy to pass on any pitfalls that I encountered.
The front end is much improved by some of the Brassmasters bits - slidebar support bracket (adds a lot of strength to the very flimsy slidebars as well as looking a lot better), cylinder details, lamp irons, AWS bashplate etc, plus the Gibson bogie wheels tidy things up a lot in my view. Definitely replace the smokebox door handrail, especially as you need to replace all the boiler handrails anyway. Crownline coupling hook plus a Smiths screw link work well.
Don't even try to use the white metal running plates - they're for the old Black Five and I doubt they even fit that. I made my own out of black plasticard, as well as some small support brackets. Plastic weld these together and I'm sure it is way stronger than the superglue bond on the white metal inner edge that was suggested. If you start with a Black Five with the correct boiler fitments, and a rivetted/part welded tender, I'm sure that makes things easier too. Have some brass rod handy for the reversing rod, NS and copper wire of various grades to fabricate the sand pipes, AWS conduit, some other pipe/tube/run from the Driver's side to the reverser, Caprotti shafts needed a fair bit of tidying up and they are quite soft old white metal. Beware! Make up your own Caprotti motion support bracket out of plasticard or fret waste. Generally, much fettling and filing of white metal parts is needed, but they do fit OK when you've done that.
Oh, and remove the under-smokebox infill before you start, and don't stick the double chimney down with NASA strength glue until it's in the correct place........!
Iain