Welcome to the forum Rob.
We only have a limited number of TE builders on the forum and not many of them are from your part of the world though our member Paul may be able to help, this is his 6" engine thread
I would suggest you join Traction Talk Forum and then ask in the miniatures section. Off the top of my head there is Doug Mellor who has a 3" Fowler A7 built partly with castings from MJ Engineering here in the UK, castings from his own patterns and fabricated parts. There is also Suctionhose (Ross Bishop) he has a 3" maclaren and has recently started a 3" Fowler ploughing engine, both from UK sourced castings. There are a couple of others as well. (You will need to join before you can see the two engine links)
J
Edited By JasonB on 01/06/2016 08:02:58
Edited By JasonB on 01/06/2016 08:09:47