No heat!

[rsjon]

2014 2.2 dropside RWD with no AC has no heat output from the heater. It has only done 35k.
Coolant level is correct. Engine temp is correct. When warmed up rad and top and bottom hoses are hot.
Both pipes to bulkhead for heater matrix are hot.
I suspect the flap motor is faulty and not moving the hot/cold flap when instructed to by the hot/cold knob.
Anyone any experience with this? How best to access flap motor? Any advice?
Thanks,
Jon.