Telephone Line Fault?
I have two extensions running off my master socket, but they're not
hardwired into it, I have a 1-to-3 way splitter plugged into it ( only two
ways used ). So, that means I already have disconnected the extension cables
already, as you suggested. However, you have reminded me that I haven't
removed the 1-to-3 way splitter so I'll remove that and plug a 'phone
straight into the master socket,
you need to plug 2 phones into the master socket, not 1. If both give
the same probem its BT's fault, and they should fix it free. Plugging
just one in doesnt tell you if the problem is your phone or BT's line.