Auto Gear shift not releasing from park

Holden Frontera '99 v6 3.2l ( yes its a Rodeo)

Hi All

Starting to have a niggling problem with the auto gear shift.
Sometimes I cannot get the gear shift to move from park as the solenoid actuator is not operating especially whan left overnight.
I guess it may be actuated from the Brake light switch attached to the pedal.

In all probability which is the unit that will be at fault because one day im gonna get stuck in park permanent.

Thanks in advance