Futaba 3GR 2.4 - No throttle / brake

[safk]

Last night I raced the car in heat 1 (Futaba receiver)& all was fine, I changed the battery in the car & turned it on for heat 2 & have steering but no throttle.
Bummer I think, perhaps it has lost it's end points as I have had this with the SkyRc Toro 120A esc before but when I try to re-set them I can set neutral, full throttle but it does not recognise full brake.

I then try the spare car which is programmed as another model in the TX (FrSky TFR4 receiver) but again fitted with a SkyRc Toro 120A esc & I have exactly the same issue & run into the same brick wall when trying to re-set the end points in case it is the ESC in car 1 that is playing up.
I revert to car 1 & swap the steering & ESC plugs in the receiver & the throttle lever works the steering suggesting that the lever itself is OK but the steering lever doesn't magically fix the throttle brake problem.

When I got home I then tried 2 other cars that are also set as different model profiles on the TX both with FrSky TFR4 receivers but one has a Absima esc & the other a Turnigy Trackstar ESC & still have no throttle or brake on either of them either (But didn't try re-setting end points on these as all was working fine at the weekend)

I have tried the switch on the top left of tx in both positions even though it's switched off.

Can anyone help with this as it's driving me nuts & I can't seem to narrow it down by process of elimination.