Bit of an update... the connection seems a bit better.
Here's some tests I've just done:
I'll post some more results later tonight.
And my thinkbroadband monitor seems to show some kind of improvement over what it was last week...
Current graph (ignore the red part at the left, I had my router set to deny ping requests:
Monday's:
However, what I don't understand is how my mate (connected to Acton) gets this for yesterday:

---------- Post added at 19:38 ---------- Previous post was at 18:11 ----------
Still not looking too bad @ 19.30