Thanks for the reply, however given the complexity of this I decided to called DentWizard instead rather than risk any further damage to the door!!!
The DentWizard man came out to my work place and did the job in about an hour. Interestingly, he didn't remove any door components, instead he used the hole that sends the cables throught to the rear door, and pushed the dent out from behing there - clever!!!
Good as new and good value I thought, defintely recommend them.