Presumably though you've all been refunded, because the Consumer Credit Act* says:
"The debtor under a regulated consumer credit agreement shall not be liable to the creditor for any loss arising from use of the credit facility by another person not acting, or to be treated as acting, as the debtor’s agent."
Ultimately, it's the retailer who takes the fake card who loses out.
*Section 83(1). And, yes, I'll try and get out more.
Latest update: According to the local freebie rag, Budgens on Moyser Road SW17 has been targeted as well. Not a problem for most of us, as last time I looked they had no good deals going on Zipp 404s, but at least one Agreeable lives close enough to get his beer and fags from them
.