Yes, this was standard practice for some "professional" grades in the Civil Service. In fact, the entitlement was known as Professional Added Years. It's availability was based on the concept that the Service wished to employ persons with extra years of training or experience. Sometime the Vacancy Notices specifies an explicit no. of years of experience as a minimum requirement. As the previous poster has stated, a deduction is applied to the Added Years corresponding to one's Pension Entitlements gained outside the Civil Service.