Well to my surprise I received a reply to my email this morning. Here it is:
"Our Olympic Gold Medal Winners stamps and our other Olympics stamp products have proved to be extremely popular and demand for these stamps is unprecedented. Our Stamps & Collectibles Team in Edinburgh is working round the clock to process and despatch orders however, it's possible that this could take up to 10 working days from the date the Olympics ended.
If you haven't received your stamp order by Monday, 27 August, please get in touch directly with our Stamps & Collectibles team and they'll be happy to help. Their direct email address is [email protected]
Thanks for getting in touch and I hope you enjoy your wonderful stamp collection when your order arrives in the next few days."
They seem to have forgotten that Monday is a bank holiday (albeit not in Scotland). So I'll give them till Tuesday and email the stamps team then if still no joy. CM you might want to do the same, In the mean time I'll probably check out the PO this pm.