Ranger
Can you confirm please.
Is it the key that will not turn, or is it the engine that will not turn.
Had a problem years ago wit a Rover 45, the key would turn, but not able to turn starter, the garage was logging the fault as engine would not turn, till I pointed out that the engine was able to turn, after the starter turned.
After 4 visits , replacing battery (under warranty), it was traced to a badly corrode start signal wire, which was what I said to garage at the first visit
So do not tamper with the ignition switch until definitely sure