Yeah, in my eyes BT cram as many connections together which is why its fine from like 1am to 3pm and then it drops a little in the evenings.
I have it drop down from 310Mbps down to 45Mbps just the once and I phoned BT to moan about it, I did ask if I could be moved over to another block of connections, which BT said they will look into it.
But recently I have only seen it drop down to as low as 200Mbps, but I am not checking this all the time, only when issues happen my end.
This is my current speed results from speedtest.net
as you can see its still not that bad.
The issues I am having is I am still getting loads of buffering on normal HD Streams (1920x1080) etc, especially on Twitch where its buffering every 10 or so seconds and often freezes for a few seconds then starts again.
The speeds is there but I think the quality isn't.
I noticed your latency is rather high for FTTP.
This is my result from that same Preston server
and I still get lower and I am miles away from it.
is what I normally get most of the time.