Help required, 90 rear door lock......

I am having a problem with the rear door lock on my 90. I changed the whole mechanisim, and fitted a new barrel lock. The problem is the key does not turn all the way round to engage the lock, and from the inside the little lift up lever will not lift to the top and lock it from there either.

The lock worked when it was on a previous vehicle, although as it had no key, I could only try it from the inside.

I have been trying all sorts for a week, and if I can get it fixed my wife will lock me in it.

Can any one help?

try turning the key realy slowly mines the same if i rush but do it very slowly and it will lock most times