Re: What next?
"cyclists appear to be able to fit whatever flashing lights they like. I think standard bike lights should be a thing. None of them should flash."
technically in the UK road users are not allowed to dazzle oncoming traffic so badly set or super bright cycle lights are illegal to use. Flashing lights *are* legal but only if used alongside a legal, permanently lit lamp (some lamps use a single lit LED specifically to circumvent that rule).
This isn't a case of being legal or illegal, it's a simple case of no enforcement. Much like the muppets who demand a 20mph limit to control traffic because "nobody sticks to the 30mph limit" but can't see that the 30mph isn't being policed ...