They could refuse, continue doing their job on the side, or just take the temporary pay cut to enjoy a close to do nothing job for a few years. I don’t think that’s anything to be concerned about. An MP gets over £90000 plus expenses, that’s triple the median salary. If those that earn more want to self select themselves out of power, they can definitely do that. That’s only about 4% of the population.
https://uk.indeed.com/career/software-engineer/salaries https://uk.indeed.com/career/surgeon/salaries
I don’t think you realise how much £91000 + expenses actually is in the UK.
And currently the house of Lords is a bunch of old geezers that don’t know anything about anything, so yeah, taxi drivers and farmers would be a welcome change. They actually talk to normal people once in a while.
And again, if they feel like serving the public when shaping policy about their profession is important enough, they should be happy to take a pay cut for a few years for the greater good.