The “UK” based site is highly unlikely to actually be based in the UK; it is possible to get a UK domain/server from anywhere in the world. Otherwise it would be tracked via the ad networks funding trails and closed down.
MHRA have had other sellers turned over for just Medicines Act stuff (like Modafinil, which is relatively harmless) let alone class B. 6am dawn raid with Police (often armed units); media tipped off as well. The authorities are not daft and know that otherwise well behaved middle class students of pharmacy or medicine get caught up in this stuff.
Even “legal” (or not yet controlled) stuff like etizolam can’t be openly advertised here as the vendors can be shut down for encouraging consumption of toxic chemicals, using common law from the Middle Ages used to regulate sales of poisons (these kind of laws exist in every country of the world).
That some RCs/NPS are not yet controlled across the whole of Europe is more by accident rather than design (some governments don’t want to lose the tax revenue from RC vendors (which often are legitimate businesses who sell other chemicals for such things as making computer circuit boards or cleaning products) nor harmonise their domestic legislation with the EU; I suspect many governments begrudgingly realise that at least they can keep track of these vendors and they rarely get into other forms of criminality unlike traditional drug dealers; or stop with selling controlled substances (as there is less hassle) but once enough people end up needing public healthcare treatment those may get controlled as well.
I work in a place where kilos of benzos and opiates are brought in every month for the patients; but today there are all sorts of security measures against diversion, locked cabinets, random checks, everything counted to the last dose. It wasn’t always like that but diversion/loose prescription in both NHS and private organisations caused a lot of corruption and bad practices that were endangering people.
More recently mephedrone was initially thought of as “harmless” until people forund out the hard way it caused all the physical and mental health risks of long term MDMA use (+some unique ones of its own) far quicker.
