Update 09/03/2012:Well, after yesterday's rearranged appointment being rearranged again for this morning, the engineer, ANDY, has just left.
He has left me in a bit of a state really.
Andy has visited previously, but neither of us could remember what he did last time (or was instructed by BT not to do).
My sync speed (following a BT reset, requested by Andy) has ended up at 35322k & these are throughput speeds:-
It is obviously early days yet & errors are starting to clock up (not too quickly yet), but today's visit seems to have finally done the trick after waiting for more than 7 months.
To say I am a reasonably happy chappy at the moment is a slight understatement.
A BIG thank you goes to Andy for listening to me & looking at my evidence.
The IP Profiles graph covering the last 7 months or so seemed to be the "clincher" that made him request the BT reset.
Paul.