I have heard that you have to use a special type cake for tt cakes, rather than my usual fluffy ones, so I want to know what you use for topsy turvy.

I have heard to use something firm like a pound cake. I have only did a TT once and used the durable cake recipe from this site. It turned out fine.... others have used the WASC and that it has also been fine.

Please also see:

http://cakecentral.com/cake-decorating-ftopict-697034-.html

HTH