A bit late on this one (home PC still down

) but as the shop keeper I know who this is. I'll check the records tonight to see what's happened, but can't help feeling slightly responsible.
Name and shame isn't a good idea as there could be a plausible explanation.
HOWEVER. If there's a way of configuring the shop software to automatically apply the £10 rule, then I'll find it. If not I guess I'll have a bit more work to do to enforce it.
I could always disable the pay by check option leaving just Paypal and Nochex online payment options. These can be used even if you dont have an account set up with them, all you need is a debit or credit card. This course of action would also save me running to the bank when people finally post thier checks.