done some diagnostics and my conclusion some kind of congestion between sky and tbb.
my pings to bbc.co.uk are solid and dont reflect whats on tbb and testmy.net has a single threaded speedtest which is fine on my line.
Who is exactly to blame tho no idea although I am leaning towards sky as tbb make an effort to make sure no congestion their side.
Ping statistics for 212.58.244.22:
Packets: Sent = 314, Received = 314, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 6ms, Maximum = 9ms, Average = 7ms
speedtests on tbb are fast multi threaded but slow single.