Well you were right Granny McGrath, wiring changes were needed, well really just one and a removal of another. Problem was when some dipwad removed the cylinder and prox's from Tool 10 they decided to link out tool 10 up prox'x signal wire back to the PLC. Instead of putting Tool 10 Up wire to +24v like you would expect they connected it to tool 11 up prox. Rather a strange thing to do as either they must have had to change the ladder or the ladder did not have any real interlocks in place. I think the former as I cant see the Germans doing a ladder that was not watertight.
There was another problem, the Tool 10 down prox wire had been chopped off and left hanging, this had linked out two of the other prox's (tool 2 Up and Tool 3 down) so that there were false signals going back through to the PLC.
One last issue was the prox on tool 1 Up was too low, this meant when fully up the prox had been passed so was not being seen, simple loosen of the set screw and adjust and its fine.
Now all I have to do is wait for the cables to arrive so that I can make up a serial connection between PLC and Computer and I can then test out the ladder

Hood