passenger key won't turn in door lock

Hi, All

As in the header, the passenger door can not be unlocked via the key.

Key inserts OK but refuses to turn. I suspect that the lock does not fit the key (I'm not the first owner .....)

Problem is - I can't get the key to turn the required 60 degrees to remoce the assembly.

What am I to do ? I watched the locksmith use a vice grip ( ) on the ignition key when that essembly broke two weeks ago. Maybe I can do the same ?

Any pointers on how to remove the assemly, replace with a new one (from a dealer or used) and even coding the lock ?

any ideas will be most welcome

TIA