no revs at all in any other gear including neutral?

So, this happens when the engine goes into limp mode which is usual due to a buildup on the throttle body.

Here are two guides that should help you fix the problem:.

https://www.2carpros.com/articles/reduced-power-limp-mode

and

https://www.2carpros.com/articles/throttle-actuator-service

Please go over these guides and report back.

Thanks Ken L, can't try your suggestions until the weekend because of work, but still don't understand why throttle works perfectly in "Park" but no other gear position! Also, after disconnecting neg lead on battery car/spanner light goes out and all gears/revs all work ok for about 6 minutes, the light comes on back to no revs, this is not "limp mode" as the car is only creeping in its gear, any resistance/incline no movement, so would never get you home or to garage!

To be sure we can run the codes.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please go over this guide and report back.

Thanks Ken, I'm old school (points, rotor arm, condenser, distributor cap, etc.,) I'll have to buy a code reader tomorrow I suppose for this computer stuff, although AA man plugged his in at the scene, and it said no faults! and just so there's no misunderstanding it is the car with spanner light that comes on, that stops revs not engine management light!
Dave

Yep, that is in limp mode with the light on there is a code, so I am not sure what the AA person did. One you get the scanner let me know what comes up.

Hi Ken, got scanner and plugged in not much help, shows connection profile to car screen changes and says 2 faults detected, screen changes automatically after a few seconds, with read codes, erase codes etc., but when I press read codes it says "no fault codes stored in module" I tried it several times, also scanner lists monitors as all being N/A not sure what that means! On the practical side I've checked all wiring connections/plugs on sensors etc., no obvious damage /dirt/ corrosion, nothing changes, starts up in the morning runs beautifully, no car and spanner light on, can drive around as normal 30 /40 mph all gears changing normally for about 7 mins (between 6 and 10 minutes) then car and spanner light comes on and no revs accept if gear lever is in park position, also noted that to move lever out of park must put foot on brake pedal, (standard auto safety measure)but if I press brake pedal and leave gear lever in "park" it will not rev when I press the accelerator pedal unless I release brake pedal then revs normally. Any ideas, guesses, answers would be appreciated. Now torrential rain has stopped and I'm not working till the weeekend I'm going to strip down the throttle components as per your first suggestions.
Dave

Yep, it sounds like limp mode for sure I would clean the throttle body which should fix it. Let me know.

no good stripped down and cleaned throttle body, with some carburetor cleaner it wasn't particularly dirty, but now its shiny clean in and out, reassembled, tightened up disconnected battery as scanner won't read or clear any faults. left overnight started up this morning same thing run drives perfectly for 7 minutes then no revs, borrowed a working throttle pedal unit and connected up just to eliminate, exactly the same still no difference.

Okay, if you have no codes and the car goes into limp mode you may have a PCM that is going out. The only other thing I can think of is if the engine coolant temperature sensor is shorting out when it gets hot.