Still had the issue after replacing the worn out motor brushes. Embarrassingly enough the culprit turned out to be the battery! Got ahead of myself and didn't check the basics first. Thank you for the help!

Sounds like the same basic design of controller BT use on the old DC stuff in Europe.

I'd physically double check the traction fuse as I've seen issues with burnt fuses causing odd throttle issues even though a multimeter says the fuse is fine, I have also seen these type transistor panels burn transistors out.

Have a sniff of the panel, if it smells burnt you then need to investigate further.

There is only 4 self tapping screws on the back of the panel that holds the plastic top on - be warned that opening the unit normally voids any warranty / service exchange return in the future & mind the capacitors inside!

As I said before we don't get to see the Prime Mover stuff over here in UK but it sounds like it's a basic BT parts bin DC equipped machine.

Yes it is a 24V DC Machine. It is a stand up aisle lift, it uses a "joystick" type throttle not a pedal. I don't know if it is Atlas Copco but the drive transistor is in fact grey with the LED's you mentioned. The brushes in the drive motor are quite worn so we will replace them first and retest. Thank you for taking the time to reply!

Is this a DC machine?

We don't really see the Prime Mover stuff here in Europe but from what I gather bit's of it are based / used on the older BT machines.

If it is a DC machine & if it is the same drive system as BT Europe use I'd check the microswitch inside the throttle pedal assy as the roller wheel can get a flat spot & cause odd issues like this.

Is this the grey Atlas Copco transistor regulator with 1 green, 1 yellow & 2 red led's fitted?