A big thanks to everyone that spent so much time to help.
I've decided to continue to try the Swytch kit for my 1st conversion. They seem to REALLY push the front hub kits (ease of fitting) instead of rear hub kits but I'd rather fit it where it would perform best (even if it does take 15mins longer to fit). What do people think please?
Also, you can pay an extra £20 to upgrade to a freehub/cassette instead of the standard freewheel. Opinions appreciated please?