Okay, final update (for this problem). There was an unholy convergence of factors.
One, the phone system in this house came out of the ark, a star configuration from a brown junction box on the wall - all sockets renewed from a single master socket (Maplin supplied), any and all tree braches and twigs touching the line removed carefully with loppers, young trees likely to interfere with line removed.
Two, had my doubts about a BT DECT phone set, so they've been replaced.
Three, Belkin stats examined and something didn't sit right, so new Linksys WAG160N installed - lo and behold constant connection at 1856kbps with no drops. Here's where it gets better - the Belkin hed been replaced under warranty already and the account had been initially set up on its predecessor which died after three months service. This leads me to....
Four, a speed problem raised with Virgin which they responded to on Saturday afternoon, it appears that both Belkins were soooooooooo unstable that they had fried the IP profile.
Upshot, the line is currently being retrained, IP profile was set at 1500 kbps this evening, can even read the ITV F1 website in seconds (try that at 130 kbps).
If anybody can learn anything from this it is please give serious consideration before parting with hard earned cash for a (
) F5D8631 Belkin N1 router. I have yet to decide on its fate , it might be allowed out as an access point, or used as table leg support.
But, Thank you everybody for your help, in particular Roseway and Kitz. Bit of a learning curve so thanks for advice and patience and not calling me an idiot too much. All this wouldn't have happened if, in this village, we weren't so pathetically grateful to get service, then we find out someone 100 metres away else getting ten times the speed......
