just to say thanks for all the advice on the marker pen on upvc.
heres what i found, most of the ink came off with stain devils liquid for inks small yellow bottle available at tesco. i tried permanent markers on upvc at home it brings them off easily even after drying, when i got the marker on the door it was so hot it dryed instantly i think this was the extra problem, when most was off it appeared that some had absorbed into the plastic leaving a light blue mark, i removed this with ten minutes rubbing with upvc restorer, the line came off slowly but my cloth did turn slightly white so it acts something like t-cut, importantly it didnt scratch or show any signs of damage afterwords. job was a success! graffiti remover also seemed to work but needed leaving on and i didnt fancy comming back to a big hole in the door, once again thanks to all who responded and just thought i would share my findings incase anyone is unfortunate to be in the same situation. once again many thanks,
regards steve