Yes, I do - it's already happening. Here's a few for starters:
twitter.com/uk_domain_names/status/1345154426978361344
Some of this is temporary whilst people see the lay of the land, but the change in VAT rules is also putting a lot of companies off by the looks of it.
The one I'm personally annoyed about is lubera.co.uk, as I've bought loads from them over the last few years, and they've said they're not shipping anything to the UK until 2022 or 2023 at the earliest. www.lubera.co.uk. Brexit is going to have a massive impact on plant and seed supply I think.