Official Referral Statement (as requested above)
I was (not so obviously) talking about American peanut butter there, not British. But yeah, I would expect a spike in the UK if supply runs low and there's still some time left towards the end. However, it's difficult to say because time may be so short. There's only until April 2 "at the latest" until the "consultation and advise process for invoking temporary class drug orders between the Government and the ACMD" is over. Yet prices have not spiked or dropped dramatically yet so far as I know. I'm not from the UK or familiar with this process, but it doesn't sound like the April 2 date is the actual ban date (just when one important part of the process is scheduled to be done). I don't know how long it takes for a ban to take effect after the advising process is over. It's fun drugs we're talking about so my guess is it's a fairly quick rubber stamp thing to make them banned.
EDIT: People may be able to have some minor sway over the process if enough UK citizens write the Home Office and their more progressive newspapers with their anti-depressant MXE stories NOW. It's likely the end of recreational MXE, yes, but if there's medical or scientific interest maybe it could be eventually classed in a way that allows easier access to MXE for researchers investigating potential medical uses (long shot, but it's something).
No. I'd be curious if anyone knows of a recreational drug that's ever been temporarily banned and then unbanned because either the UK or US government was unable to "prove" it warrants permanent ban during the ensuing year. I think maybe ephedrine had "something" like this happen in the US (because there was lots of money behind it). Still, at this point all ephedrine is limited to very low doses per tablet and is almost an order of magnitude more expensive per dose than when it was unregulated. Oh well, now there's the largely untested dimethylamylamine to fill the void (and the beat goes on).