Bruce you were asking about some good ideas for cooling and I was also wondering about my Sea Fury. So what I was thinking about was using helicopter engine cooling fans and/or modifying them to work. If your interested here are some links to different size fans. In the case of the mossie if one leaves some distance between the exhaust manifold and the nacelle side then that could be the hot air exhaust.
Even if one uses just the fan blade to move air around it should help to cool the engine. Even the shroud can be modified to fit the application. Don't forget heli's work a lot harder than airplane engine do and with hotter fuel, usually, so if it works for them it should work for us.
Oh I put the BT mossie on my xmas list and told the wife that I already have the engines so I'll most likely will have to reread this whole thread again, just like a good book.