Is there such a thing as or does anyone know of a proprietary telescopic TV Ariel pole that can be affixed to the cab in some way that will stand the test of everyday use and adjustment?
Get a Harris decorators pole from b&q, also one of their cheap square Ali shelf brackets. Bolt bracket onto top of pole, will slide into aerial, either horizontal or vertical as necessary. Can also he used as height gauge, strap putter-througher, etc. Lasted over 2 years on my old unit, will extend up way above the trailer. Get an app called antenna aligner if you’ve got a smartphone, will also tell you where to point it.
scaniason:
Get a Harris decorators pole from b&q, also one of their cheap square Ali shelf brackets. Bolt bracket onto top of pole, will slide into aerial, either horizontal or vertical as necessary. Can also he used as height gauge, strap putter-througher, etc. Lasted over 2 years on my old unit, will extend up way above the trailer. Get an app called antenna aligner if you’ve got a smartphone, will also tell you where to point it.
Good man! Thanks for that - off to B&Q at the weekend. 
No probs. The bracket I used was their cheapest one, about 4" x 6", with red plastic caps on the ends, about 10mm square. I also made a holder for it on the back of the unit witha short piece of scaffold pole, with a threaded wing bolt tapped in to hold it securely. Sadly, forgot to take it all off the unit when I left there. Might see you in b&q at the weekend 