I know that feeling all too well. A little while ago one of my Mordaunt Short Signifer 12 inch woofers suddenly developed distortion. Thinking that it was probably a bit of sag in the rubber suspension I turned the driver around 180 degrees ( not straightforward as the driver's magnet is bolted to the rear baffle with a steel rod at a specific torque as well as four hefty set screws on the front ). Anyway I reassembled everything and the distortion was even worse so dismantled it all again and rotated the woofer back 90 degrees, put it all back together and phew, distortion gone. Not too sure what I would have done if this hadn't worked as the chances of finding replacement drivers for the 35 year old Signifers is pretty unlikely, I guess I might have been able to get them re coned but even Mordaunt Short were unable to suggest where I could get this done. So I certainly understand how you felt with your recent emergency Russell.
Turntable
Toshiba SR-370/Mission 774/Van Damme cable with MS Starline plugs/Ortofon Quintet Black
CD
Cambridge CXC transport/modified Musical Fidelity X-DAC/modified Musical Fidelity X-10 V3 tube buffer
Network Player
Cambridge NP30
Amplifier
Denon HA-500 head amp/Nakamichi CA-5E pre-amp/Chinese passive RVC/Proton AA-1150 DMC power amp
Speakers
Mordaunt Short Signifer on original factory stands
Cables
Mogami with Rean Neutrik plugs/NVA LS5
Headphones
Sennheiser HD600/Sennheiser HD650/Koss Pro4 AA