When I was on my Flying Scholarship at Norwich, there was a part-time instructor that owned a Slingsby Firefly and a 310. After some work was done, he felt that it was flying slow and wondered if the gear doors were hanging, so I was asked to video his 310 from a 2nd 310 (G-EGEE), whislt they did some comparative power/speed checks.
Lovely aircraft, felt huge inside after C150/172s, but seemed to take forever to do the holding point checks!