Just to update, the main phone line (01727 839926) has now switched over so and is wired back into the studios. So use them for phone interviews as normal.
On our new tariff, our first 60 mins to UK and International (from a list) landlines is unmetered then incurs a normal pence per min cost. For mobiles this is the first 10 mins. Our previous supplier billed us from the start of every call.
If anyone makes lots of regular calls or 'unusual destination' calls and wants more info on charges it costs RV, then let me know and I can share the tariff details.