Good morning, we did have a technician call around and do a temporary fix by adding an attenuator to the line, it has helped, but the problem still persists. He stated that Virgin media would be in touch within the week to make arrangements for the fault to be resolved. I've not had any further communication.
I've had this problem for months, thinking it was my devices that needed replacing until I went to stay at friends for a few days and had no problem whatsoever with their Internet connection.
Thanks again for your help, regards David.