As usual.....
.....thanks to all who have replied. At 0630 this AM all was back to normal, ping was 81ms and the download speed was 0.97Mbs. As I always shut everything down when I go to bed, perhaps there was an element of mixture's offered solution at work.
SD. I got lost in that tracert site and couldn't work out which bit was going to point at possible pinch points. Oh, and I was offered all sorts of software to buy which were equally meaningless.
That's the problems with this computing lark - with a little knowledge you can work what question to ask. The real barsteward is trying to understand the answers which, almost always, assume a level of knowledge that isn't there. It's like learning a phrase in a foreign language and getting the pronunciation pretty good and being completely floored by the torrent of furrin that comes back to you. Hey ho we live and learn - but slowly.
The Ancient Mariner