Hi Will,
The Steam Workshop (
www.steamworkshop.co.uk) have some 3" Burrells in at the moment, there is only one on their website at
http://www.steamworkshop.co.uk/portfolio/3-burrell-11/ but I think there may be others that have not been listed yet. Give Simon a call on 07816 963463 and he will tell you all about them and send pics - tell him James Littlewood sent you.
I'm not on commission, just a satisfied customer and friend of him for several years.