Just to finish this thread.
Since end of April speeds have stabilised at around 4.5 although tonight at 22.50 up to 5.6. So problem seems to have gone away but I am no nearer knowing what caused it in the first place.
With regard to differing speeds between laptop and desktop, that I have resolved. The problem here is my network card on desktop, this is an old one, probably 10 years +, new card should resolve speed difference.
Once again thank you for showing interest in my problem, speed issues do seem to be recurring theme, and helping me out which is very much appreciated. I guess until BT upgrades the network we are all going to suffer speed related issues.
gom
