Hate to be pedantic but the BFR does exist and apply in the UK. The PFA conduct Biennial Flight Revalidations to maintain currency for PPL and NPPL pilots through their coaching scheme. This allows for people with single seat or two seat PFA or vintage aircraft to get their licences revalidated with appropriate and experienced coaches. It would be inappropriate for someone who only flies say a Tiger Moth or Jodel, from a farm strip to have to fly a Piper or Cessna once every two years.