Thank you LPBeir and Mimizkitchen. Those tips are very helpful.
I have been reading up on bake even strips... they look like a good idea. I haven't seen them sold in the UK so once again I think I will have to order them online.
Once the cake is even enough, turning it upside down seems like the way forward so the top is flat. I will certainly try the frosting wall idea - sounds great! Thanks for the tip.
I spent the whole day yesterday making sugar flowers and miniature bride and groom. For the bride and groom I gave up on sugar dough however and used fimo! Which is sort of cheating I know but working with the sugar dough was proving to be a nightmare. I'm pleased with the fimo results and will just warn the bride and groom and they can't be eaten!
Next I'm studying the Cake Bible to find the perfect recipe for the cake itself.