I've spoken to the ASA, who say

The credit advertising you object is a non-broadcast ad that falls under the Consumer Credit Act 1974 and subsequent regulations. That being so, the ASA has no power to intervene. I’m sorry we can’t help but I suggest you seek advice from your local Trading Standards department, whose details are available from your local council or phone book. You might also find these websites useful: http://www.tradingstandards.gov.uk and http://www.lga.gov.uk.

So, I've raised a query with Consumer Direct.