Sometimes when the queen goes to start the caravan the key will not turn we have played with it and it appears it is something to do with the steering wheel being locked and the turning the wheel to freee the key up any ideas seems to be getting worse

 

my 96 did the same thing. there is a cup on the end of the ignition switch inside the column. It gets worn and breaks.
A new ignition switch can be installed by a auto locksmith for ~$50.

Do it before it breaks.