Hi John and Martin,
I have also bought a pair of RL140 speakers for refurbishment.
Visual inspection will reveal whether the drivers have foam rot, It only affects the four mid bass drivers which have foam rather then butyl surrounds. Recone Labs in Huddersfield have done an excellent job of replacing the foam rings with butyl, they will also repair the voice coils if there is any damage, ask for an estimate, but bare in mind these are not cheap speakers.
There is information a visual guide on dismantling RL60.2 and recovering them on the sight, check some of the posts I have made.
I am also replacing and upgrading the capacitors and internal wiring capacitors were sourced from Wilmslow Audio how are very helpful, cost around 70 pounds for upgraded capacitors, they are rather large but will fit inside the cabinet.
Good luck!
Dave