Wrongly Billed Home Phone

[#1]

Hi Liam and thanks for your reply.
I will try to answer as honest as possible.
First of all I live on the second floor on my own so no chance of people sneaking in or others using the phone. All calls were made in my absence and bizarelly some of them while I was there.
I did dial the numbers out of curiosity and one of them was Bradford City Council (I live in Glasgow...) some other ones were for Sky Broadband(call centre) and others were residential numbers South of England where I do not have any ties...
Nothing I have plugged in dials out. I run an Apple Mac and the modem is disabled on it. Only use wireless to access the web. Besides all numbers dialled to date are 'manned' and not automatic centres.
I think my phone allows me to change channels so I may try that option but it is the best I can think of.
I agree with you that if someone is indeed picking up my cordless signal then it will be very hard to prove. I do not currently have an old fashioned phone to plug in but I will try sometime soon and see if this works.
For the time being though, I am at a loss and I keep having to check my itemised bill on line and raise tickets to PlusNet...sorry Mand 
Hope this clarified a bit and thanks for your help.
Michael

[#2]

Do you make outbound calls a lot?
I wonder if PlusNet were to apply outbound call barring from your line as a test, whether or not they would still get call data from BT for your line.  If so, it may prove it to be some kind of administrative / crossover error in billing rather than someone actually using the line.

[#3]

Until you can get your hands on a corded phone (you can pick them up for less than a tenner from Argos), why don't you unplug your phone during the day and see if the spurious calls stop for the hours the phone is unplugged?

[#4]

Hi All
I will certainly try to unplug the phone during the day and see what happens then. As for making outbound calls, well not really and I am happy to use my mobile but I do need it for inbound calls as I get a few of them (not in the day obviously!)
I will check and report back in a few days.
Thanks Guys
Michael