Thanks for your help so far
Following on from a chat session I have a fault logged with SMT. See extract from transcript:
Your being passed over to our Service Monitoring Team (SMT) The SMT will monitor the customers connection and will call the customer back .I will now arrange a call back from the SMT with your preferred time .
Ideally the speed should be stable but i have done the checks and i have found that your line is not stable and it is intermediate so checks by the second level of support they will monitor the line and will get back to you
Yes, I am pretty sure that one of the taglines for Infinity is "even at peak times..."
yep they said to me no throttling, BT is a joke, tbh id advise you to leave and go with virgin media. they are much better and dont let anyone tell you they arent. you can get there 100Meg package for cheaper than bts 80 and youre more than likely to get full speed. something people are rarely gonna get with BT.
For your info, I got a phone call back from BT saying that 'they had identified issues on my line and has now been resolved", however, I had some spare time today, (ok - a lot of spare time) and pretty much plotted my download / upload speed to varying granularity