Long's are very good on the RF stuff, and they have a great stock of kit also. The cable via the booth should be fine, lots of people did that for year's, many Taxi's s well, probably good advice would be to remove the aerial over-night, especially if it's wet, as you might find a little bit of water travelling along the cable.
That's it exactly. My plan is not to have it hardwired in so that if I'm not travelling or I'm parked up the kit can and will be removed. I have my eye now on a couple of radio's... President Barry II or a CRT One N.