Bristows use 123.45, because it's cheap in fact it costs them nothing. If they moved to another frequency they would have to pay for it which certainly goes against the current management thinking of spend nothing, invest in nothing and if you do have to buy something make sure it's the cheapest piece of !!!!! on the market which won't last.
They'd be more likely to equip their aircraft with Barbie Doll Walkie Talkies before getting a dedicated frequency.
