I will post an update on my phone issue, I won't be doing any more with this.
After a week with the corded phone there were no problems, I needed to return to the dect phone for convenience with caller display etc, another week and again no problems until today with one call. All I can say is I've eliminated the face plate. I've decided to move over to mobile for all outgoing calls, I get a good signal with E E. Also the 4g broadband speeds of approx 60mb+ down and 30mb up are way better than my FTTC broadband 15mb down 1 mb up. Thanks.