Well, the "personal shopper" bit was my dear daughter, just back from Crete with - wait for it - 22 boxes of T3. What a star!
Now I will have a buffer against any future shortages.
A huge Thank You to Marz for flagging it up in the first place, hours before my daughter was leaving for Crete. Think I should be taking a holiday there myself just so I can thank Marz in person - could probably justify it on the cost saving alone.
I wish everyone else the best of luck in their quest to source supplies.