Sorry about the slow reply again, been busy and have been having trouble getting a decent recording of the noise!
But today I started the car in gear, with the clutch down and the car shot backwards I took it out of gear and re-started, but couldn't get a gear until I again restarted in first! After that the car drove ok and I could easily get all 6 gears. So it really must be the clutch/release bearing, as the sound does come from that area.
Also coming home I drove through about a foot of water and afterwards the brake pedal was absolutely solid. Never had that before!