I've been hiring people for 10 years, and I still swear by a simple rule: If someone doesn't send a thank-you email, don't hire them.
Jessica Liebman Apr 5, 2019 https://www.businessinsider.com/how-to-write-thank-you-email...
Its a follow up to previous 2012 work ... https://www.businessinsider.com/the-number-one-mistake-peopl...
"They're all messing up on something that I think is very important when trying to get a job: the Thank You Email."
You may be missing out on a lot of potentially good people.
Alternatively, maybe they're dodging a bullet. ;)
But I would definitely want to know more about the governance of an organization that can sustain such a policy as categorically rejecting a candidate (read: contribution) for not meeting an unexpressed expectation.
We already discussed you immediately after the interview. It's not going to change anything, but it might hurt your chances if it comes across as cringy or brown-nosing - we're also looking for cultural fit, and most Brits just don't do that. If you introduced new information in the email, you're probably going to force us to discuss you again, which is at best annoying and certainly burns up staff time.
So in a UK context, you're best off just saying "Great to meet you all - hope I'll get to work with you" at the end of the interview, and leave it at that.