So after messing up last night, and splicing into the wrong cable, got it working tonight! Hurrah!
A bit intermittent at first but once tidied up and secure in place it was fine did have a problem where the switch worked the opposite way round but the auto was fine - so I just switched the grey and white pins around in the module plug. All good now!
There are differences in some of the wire colours on the HR, but if you use cookbots guide and use the same pin locations in the plugs it's fine.