Question Author
Thank you Mikey! I am expecting a visit from an engineer on Thursday so awaiting patiently. I have been with TalkTalk since they first started broadband and have to say that after their initial teething troubles, I have had no problem with them, plus I am paying far less than I would with BT.
I suspect the problem must be with the router which I brought with me from my last address. I was getting a steady 38 mbs wifi with the medium fibre package. My initial speed test in the new house was slower but I am further from the exchange so this was to be expected.
I am going to look into getting a better router at some point, although I have discovered that if I use my TalkTalk mobile as a wifi connection it is not using any of my data allowance so I am accessing the internet, although very slowly via 3g.