How easy (or difficult !) is it to pipe onto the vertical sides of a cake ?
The experts make it look so easy ! I guess that's WHY they are experts though !

We use this type of contraption. As long as your cake is on a board it stays on well. Not had an accident yet.

http://www.amazon.co.uk/PME-Multi-Pu...cake+turntable

I have a turntable, but it's not an angled one.
I guess having one that tilts would make it easier.

It is just practise. Try if you can to get the cake at or near eye level. So, sitting on a low chair with the cake up on the turntable might work.

If this is the name on your number cake, how about cutting shapes from fondant using a biscuit cutter for instance....leave to dry and then pipe one letter on each shape. If you cut more than you need then you have room for the odd accident. Then you can just attach the little plaques to the side of the cake with a little icing.