I paid £10 to have the same number in both classes.
Saves loads of hassle.
Example:
Start the day with #23 for SoT
Then change to #74 for DD
Then change back to #23 for SoT
and back again to #74 for DD
..then if you're doing SoT next meeting, you'll have diff numbers again probably, and unless you're really careful the numbers will fall apart every time you remove them.
Although I think it's totally wrong to have to pay £10 to keep a number, it would probably work out cheaper over a season if you're buying numbers.
It's all a con