Neil,

Not sure of the availability in the UK, but if you want something fun then take a look at the Clancy Aviation's Speedy Bee and Stagger Bee. They are just pure fun and the .30 4str is at the top of the engine recommendations. Also, the Page Aviation's New Bee is a highly aerobatic and great looking plane that flys great with a .30 4str.

I had the Speedy Bee with a Magnum .30 4str, it was loads of fun but returned to kit form when flying at full throttle in a shallow dive the horiz stab fluttered and quickly departed..........instant lawn dart. The instructions say when using this size engine, only use full throttle for climbing!

Gary