Hello Phil
I've spoken to Dave Yorston from BBN who is organising next years Games 100 Marshals event. At one of the planning meetings I've seen the proposed tally for the event and they are very robust and cheap. They've not been tested in any inner city riots yet but I'm sure they'll stand up to that.....
Anyway the address is as follows. Hope this helps.
Pymmwenn Printing,
Unit 5,
57, Thorby Avenue,
March.
PE15 0AR
Telephone No. 01354 658215
e-mail numbers@pymmwenn.com