ID relays on bulkhead

Me to Bryan!
At least I seem to have (for now) solved a non starting issue. That leaves the transmission warning light problem to fix.
As I don’t have access to a Jaguar PDU to help narrow down the problem I discovered in another thread that I can attach a wire to pin #8 on the transmission control module and ground that wire with ignition on and that will cause the transmission warning light on the dash to flash up a code. Is this a plan or is there something I should be looking at to sort this transmission issue?

I’ve been driving the car recently and the transmission warning light usually comes on after about 5 to 10 minutes of driving. I’ve got the flash codes by grounding a wire in pin 8 method and they are: 68 - Transmission Component Slipping; 74 - Transmission Input Speed Sensor (TISS) Circuit; and 85 - Undefined Ratio.
Any idea what I can do to solve this issue? Thanks