Magmount aerial wiring

[Lightspeed]

If this is your only vehicle and it has a boot, why not fit a boot lip mount instead.
No holes to drill, and it doesn't mark the paint work (on the outside anyway).

cos its a Transit van and has no boot

You can get mobile cables with what is called a pig tail. This is a very thin 1/8th" ? short length of coax that passes from the antenna through and across the door seal. Its quite flexible and being thin is less cruched when the door is closed.

Are such cable available for CB Paul or are they only available from ham shops?