LMSC There is no free limit. There used to be a threshold below which VAT liability was ignored - think it was around £15.
The new rules came into force on 1 Jan 2021 so foreign businesses have already adapted, either by registering with HMRC or by stopping UK sales.
Worth noting that this now applies to the world and not just EU. For example, Ali Express in China now add UK VAT to small purchases during checkout.
I tried to make a <£135 purchase from a small US firm and they declined as they understandably aren’t interested in increasing their red tape. They were happy to sell to me as long as I increased the order to over £135 so that they didn’t assume VAT collection responsibilities.