I want to confirm that hours flown in a non JAR / EASA aircraft are good to log with other hours flown in JAR/EASA aircrafts.
Perhaps you should look at the definition of an EASA aircraft. Forget JAR it doesn't exist any more!
An EASA aircraft can be defined as an aircraft that, if registered in an EU State, would be required to have an EASA Certificate of Airworthiness or Permit to Fly in order to fly legally. It is not valid to assume that any aircraft that has a permit to fly is a non-EASA aircraft. The EASA/non-EASA status of an individual aircraft registered in the UK can be verified by checking whether it has an EASA airworthiness certificate (CofA or Permit) or a UK national certificate.
So, if it would be an EASA aircraft if it was in Europe, then hours flown in it must count towards EASA experience requirements. What is less clear is if hours are flown in an aircraft that would not be subject to EASA control.