I've had UK domains since day one of Nominet. Originally names cost quite a lot, don't recall was it £100 or £200? but it I think it was a one off charge no annual renewal. Ten years later they decided to dispute my ownership of a highly desirable domain name I'd had and been using since day one and for which their whois service showed me as the registrant. I proved ownership and they agreed to continue as long as I paid the ongoing annual renewals.
On another occasion they let a name of several years standing drop with no notice. All my names are on auto-renewal. Overnight the live website went dead, name immediately released straight back onto the open market. Rather than face the hassle of trying to get them to investigate and correct the situation I just re-registered it before a name squatter could grab it.
Then I took it up with Nominet. Their explanation was a discrepancy in the registration details: the business name was shown as XXX trading as YYY. Subsequent to the original registration Nominet had introduced a separate "trading as field" to the database so the data was now incorrect. They had emailed an advice but there was a typo in the email address so they chose to disregard the bounce and not to bother trying the phone or postal address (both of which were correct), and finally, rather than suspend the name they cancelled it completely.
And I just checked with 123reg through whom the name was registered (yes I know, not the best choice...), their interface doesn't offer Nominet's t/a field so the only way to register correctly is to subsequently log into the Nominet control panel and add that information.
I do just wonder if this proposed price increase is a recognition that bare .uk names (without the .co) have failed. That's to say many (most?) of those who have paid up for the variant seem not to be using it (try tesco.uk, hsbc.uk). Maybe the plan is to include the bare .uk in the same fee as co.uk.
No, I expect they're just not satisfied with those meager £60k salaries.