A former chief instructor at Shawbury of my acquaintance was posted from the Tern hill course to the SAR Flight at 'Big K'. He flew Sycamores and then converted to the Whirlwind 10, before returning to Tern hill to do his QHI course. After that, he had a mix of QHI jobs, French Test Pilots' school, air attache duties, staff tours and CI as mentioned above.
On retirement and despite an impressive logbook, he never served on a numbered squadron: now that must be pretty rare for an airframe driver.
O-D