Boots have been a PITA over this for years. I believe that the official guideline from boots is that the final decision is left to the pharmacist.
It is all very odd since they actually sell Atkins products, but they would probably say that it was because the ketostix are sold in the pharmaceutical department within the store.
They are available from your CDCs though, and Ebay.
If it's any consolation, I bought them, but they never showed me to be in ketosis even though I obviously was.