Do I feel a right pr*t !

Bent my aerial mast while backing up next to an overhanging tree branch - makes a change from the car-wash, eh? . . . . .

I've seen other posts on getting a replacement mast (~£25?), but need help fitting it.

Anyone done this who can give some advice please?

the electrical extending aerial is an add on after market thing
the true aerials are in the side windows however that is not the problem you have , the radio in the v8 is situated under the rear seat so the coax for the aerial does'nt have to go far ,it possibly has a frequency expander on it to assist in listening to uk radio ,access to the aerial base i would think is behind the boot inside covers with the relivent connections close to hand either there or by the radio, as its after market i would not think there is any soldering involved