Thanks Kelly and John for your replies.
I'm afraid that my post was quite poor in that this car has no running issues or any noises, as far as I am aware. In fact it runs very well and emissions are good. It came into me because the MIL was on and she just wanted a quick check to see if it was safe to drive. I came across Steve's post because of the same DTC (but with a description of Cam Dephaser-Intermittent Circuit), although my captures seem to be the opposite of what he described. I am aware that there are sub codes but my scanners do not give them. The solenoid seems to be doing what it should and continuity checks out according to AD, but the duty cycle intermittently switches to 100% as seen in my screen shots. What I can't understand is the very slight (about .5v) jump that seems to correspond with the 50% duty cycle when all is ok. If the ECU is not happy with the cam/crank relationship would it default to 0% (as may be the case with Steve's) or 100%?
Having said all the above, she was told at her last service that the cambelt is overdue and taking into account the dephaser problems that are numerous on Google, now might be the time to do it? I will call her tommorow and find out if she has had any noises when the engine is cold.
Many thanks for your replies as they have given me something to think about.
Regards, Bryan.