Neither Thatcher nor Reagan are far right, they are Neoliberal and therefore centre-right.
Reform’s nationalism by contrast is incredibly milquetoast. It wouldn’t even be considered right wing in much of the world. For example, if the shoe were on the other foot, and British and Irish immigration had reduced Bangladeshis to a minority in Dhaka, then the immigrants would be removed en masse (as the center-left government did with the Rohingya in response to that migration).
What do you think would happen in China if Indians and Bangladeshis mass migrated to Beijing until Chinese people were a minority? It would be a lot less talk and a lot more action than what you’re seeing from Reform.