How can this be any more legal than the 'apply for a passport' Google ads that needlessly inserted themselves as middle-men and ripped you off, that have now been clamped down on?
Is it really the case that you can appoint a company to act as an agent for one particular claim/rebate and then they act as your agent in perpetuity, even though you expressly wish to stop using them as agents?
This sounds like as big a scam as the PPI one, which is kind of ironic if it was in 'helping' people to claim PPI refunds that these vulture companies got their feet in the door in the first place.
This must be why they're so keen to get you to sign up for their 'assistance' in reclaiming things like uniform allowances which, although welcome, often aren't for more than a few pounds overall. They're obviously playing the long game, nasty little outfits. Can Martin Lewis not trigger some kind of class action against them? Yes, I know they have the 'this is what you signed an agreement for' weasel excuse, but it's patently obvious that everybody knows that most people would never have agreed to it had they been clearly informed what they were signing up for, longer term.
Even if they could be forced to spell it out in all of their advertising and soliciting - something similar to the 'your home may be at risk' that all mortgage and other secured loan companies are forced by law to clearly show in their adverts - not just bury it in the tiniest print in their contracts.