The claim that house prices increased after Brexit isn't absurd; it's just a matter of not understanding the cause.
House prices have increased all over Europe and in the US after Brexit was finally done, but generally seen as due to covid-19:
https://www.ft.com/content/2606dd0d-...1-2a089d76bdc5
That's quite natural considering low interest rates, people spending more time in their home and spending less on other stuff.