In reply to Richardlake:
We recently switched from pmr to uhf at work and the difference is night and day, they're only £12-15 per radio (retivis) and we can communicate quite easily a couple of miles away through forest. You need a licence for them but they're quite cheap.
The pmr radios (licence free) are ok provided you have perfect line of sight and no interference. I always used to just use tugs and then make sure you both had your phone in case there was any doubt.