i have just bought some Gtecniq C4 Pemanant trim restorer mainly to use on the panel below the windscreen, Can i use it on the panels on the bottom of the doors our any other parts of the car, Thanks Steve

As far as I no you can use it on any plastic surface, I have used it on RRS bottom of windscreen, front spoiler bottom of bumper, defender bumper end caps even mudflaps! With great results Range Rover Sport HSE TDV8 MY2010
Discovery 3 HSE 2007
Discovery 2 TD5 (gone)
Discovery 300 tdi
Range Rover Bobtail (gone)
90 hybrid (gone)

I think you can use it on anything plastic. There is a section on DW where they might be able to help you more, http://www.detailingworld.co.uk/forum/forumdisplay.php?f=150

It looks good stuff, I'm thinking of getting some for myself too. I've got the C5 wheel protector and that works very well.