Update to this saga.
Booked Disco into local garage that does a lot of Land Rover work to have the clutch system bled through. Took them ALL week to finally get it resolved so it was either a pig of a job to do, or there's some small underlying issue that may well surface again in the future.
However, I'm unable to drive at the moment due to bacl problems so have left clutch pedal wedged down and will see how it is in a couple of days when I'm mobile again.
Thanks for all suggestions and input though, all much appreciated.