Believe it was fixed charges. Certainly not itemised billing showing a call had been made which was answered & lasted 2 minutes 5 seconds.
Incoming calls were not billed to the Bambers, unless the operator contacted them and asked them if they agreed to call charges being reversed. Outgoing calls were calculated using a metering facility which racked up units at the local exchange. Bills were calculated dependant upon how many units were used, during fixed prime time and cheap rate periods during the day time, evenings and week-end.
I found out from a retired BT engineer, that it would have been possible to break down all the individual calls which had been made from white house farm, by carrying out work at the local exchange using specialised equipment but it seems that if Essex police went to such trouble, that for one reason or another if they did, then they have not disclosed that information!
I believe that Essex police did go to the trouble of trying to establish whether or not a call was made from white house farm to Jeremy's cottage by checking the equipment at the local exchange, and got it confirmed that such a call did take place, which was why they seized Jeremy's answer phone and five audio tapes. But, this was considered irrelevant for disclosure purposes because of the fact that the telephones at the scene and Jeremy's cottage were subject of an eavesdrop under the telecommunications act warrant as part of an ongoing drugs squad operation!. Essex police know that Neville Bamber had made that call to Jeremy, and that this call was followed by Neville's 3.26am call to the police - they knew this because of the ongoing surveillance that was already underway from prior to the time of the shooting tragedies, and afterwards..