So, provided I can get the CAA to approve my hours, by following the below requirements, I can obtain a UK ATPL, but it will be restricted for use on UK reg. aircraft.
f you are very experienced you should you should apply to the CAA for a formal assessment using FCL form 680, obtainable here.
The qualifying criteria are
more than 3000 hours total time on aircraft of more than 30,000kg AUW
more than 1500 hours pilot in command on aircraft of more than 30,000kg AUW
Type rated on an aircraft of more than 30,000kg AUW
More than 500 hours total time on the aircraft above
Able to complete a flight test on the same aircraft
When you have completed it you need to send it or take it to the CAA with original licences and log books. The CAA will tell you that you need to pass two written exams, Human Performance and Aviation Law, and pass a flight test on the aircraft you are rated on. The flight test is referred to as a skills test, it is part handling check and part IR renewal check.