Is a (British) wedding cake just a tiered fruit cake I'm trying to find a good recipe for a wedding cake. I'm going to keep it fairly simple, one or two tiers, plain icing with some small decorations. 

Many recipes seem to be variations on classic fruit cake or Christmas cake. Is that the case? Am I safe scaling up a recipe like Delia's Christmas Cake (a favourite of mine) or is there something specific about the flavour of a wedding cake I need to be sure to include or omit?
These days, wedding cakes can be pretty much any kind of cake. A traditional wedding cake is certainly more or less a Christmas cake - a dense, dark, 'matured' fruit cake with marzipan and royal icing.

However, nowadays you will find that anything goes - flavoured sponges are extremely popular. The main criteria is that the cake should be sufficiently dense to hold the weight of a tier or two. This means your standard light-as-air Victoria Sponge won't cut it - it will just collapse. You need to be looking at denser, moister cakes.

Basically, a wedding cake is whatever the happy couple want it to be!