Here...
http://www.ukrabbithutches.co.uk/rabbitruns.html
They do lots of different sizes and will modify a basic design if you want. I just got one custom made to fit with an existing hutch in the space I have available - additional doors, stronger weld mesh etc
Really pleased with it and how easily it went together. Would definitely buy from them again.
I just got a quote for a 6 x 5 one from Ryedale. Haven't ordered it yet though as I need to move the playhouse back first.
iv got a quote off a bloke on preloved for a 6ft x 3ft for my tortoise and hes said £65.does that sound about right?
I got a run from the ukrabbithutches.co.uk and its fab. it was delivered quickly and in good condition. would definitely use them again.