If you have been working in the Aviation Industry - but in a back-office job such as QA/Airworthiness/Tech Services/Records/planning - you should be able to keep your licence(s) and any types on it.
Just apply for a normal conversion to Pt 66 stating what you have been doing and for how long.
If you have been "out of the industry" for more than two years - (IMO) forget it.
If you still have any doubts phone or e-mail the CAA with your query. They will answer an e-mail but not quickly.