Hi Natalie
Thanks for your quick response.
I can confirm that I have three individual handsets (Dining Room (Main Socket); Kitchen and Bedroom) which are all connected and appear to be live but all three have the same problems outlined below.
The main cable leading from the master socket to the handset in the dining room is secure and without damage and I have done nothing recently to disturb the cable or the socket itself.
Having said all of the above, low and behold I have just checked the phone again and it is now working, albeit with a slight crackle in the background which hopefully will rectify itself in due course.
Thanks for your offer to help me to resolve the problem