ESC Kaput?

[steady_eddie]

I've been having some strange symptoms from the car recently

Mostly - sometimes very jumpy to accelerate from a standstill as if the batteries are flat and it almost doesn't have any power but they are not
Sometimes not engaging reverse
Top speed sometimes slow
Inconsistent throttle response - sometimes feels like the batteries are flat when they are not
Also a ticking noise when at standstill (not the servo) and sometimes a screeching noise when accelerating but I'm not sure if this is the slipper clutch - I don't think so..

This problem has been getting worse today I pulled the car in and changed to new batteries in case it was them but then with the throttle at full and holding the car in my hand there seems to be intermittent power to the motor you can hear it cut out briefly.
I tried to re-calibrate/re-initialise the ESC but now just has a red light - won't beep when I power on with the throttle to full to start the procedure.
Initially I thought is was the contacts of leads to/from the batteries or the connection to the motor but I've cleaned and checked these and there is no obvious problem there.
I can check voltage coming out of the lipo cells with a multimeter but I don't think there is anything else to check.
So does this sound like the ESC is faulty?

It's a reedy 450 if that makes any odds?