Hi Daz and welcome to the forum.
After you have completed the jobs you have done did you bleed the coolant system from all three bleed points with the heater set to high?. Bleeding these engines can be a right pain. If you can raise the rear of the car a bit this may also help the bleeding process. Don't give up and if you are still having problems give a one of the mobile mechanics a call.
Steve
cant comment on the jiggle valve.....have you replaced the expansion tank cap....has these can be a common failure has the preasure in the system has to be maintained
and youve had a lovely new rad fitted?