Thank you SMJ for a detailed response, really appreciate it.
I checked the radiator and it matched the ones you mention below with the issues so bypass it is for now!
Typical, as soon as I clamped the old hose so I could do the bypass it split so I ended up replacing both the hose from the Transmission cooler back to the transmission.
I have linked a couple of photos for reference.
shows the hose changes from the drivers side of the car. Old hose disconnected and hanging there, new one routed across the car.
Shows the other end of the new hose coming from the drivers side and back into the transmission. You can also see the nipple from the shared radiator on its own.
The final thing I did to complete the job for now was to place radiator hose between the input and output of the shared radiator that was bypassed. This is because the shop this morning had no caps and I can get back in at a later date to flush fluid through it as for now it just drained.
I understand that unless I tow I do not have to worry about overheating. I do live in Canada though so in the winter I assume I just need to be very gentle with acceleration until the fluid has heated up, maybe ten minutes behind the water temperature gauge reaching normal?
Finally there is nothing in my owners manual about correct checking of the transmission fluid. I have read conflicting methods with both the engine running and off. Do you have a preferred method?
Thank you again for your help. I literally read the radiator issue over dinner last night and went straight down to the car to start this job!