Update: some good news on the "possibly sagging springs". I duly gave the rear springs a super treatment withACF-50 and left the car alone for a week. Driving today there was a marked improvement in both the ride and apparent stance of the car at the rear. As far as I can tell, the "annual scheduled maintenance service and safety inspection" by a (fairly) local marque specialist in August last year didn't mention lubricating the rears springs.

Peter
2009 3-litre Roadster "Ivor", royal ivory / green