@Chrys - What do you mean by IP profile, Chrys?
@Craig - what does the recent clueless.aa.net.uk log look like? It will show you the tx and rx rates in use there, which is the real truth, not the sync rate.
You may already know that you can change the speed to be a certain percentage of this max rate. If it is set to 95% then that is for VoIP users to make VoIP reliable so if you do not use VoIP you can bang that up to 100% in clueless.
Craig when you say your download speed dropped by 5 Mbps on that date, do you mean sync rate or measured performance? If the sync rate dropped and took the performance with it then it could be a deterioration of the line, perhaps because a new crosstalker arrived, a new neighbour’s activity, or it could be a new source of RF interference or forty things.
You can try and do the usual things in your own house to optimise performance, such as getting rid of extensions, shortening wiring, using high quality faceplate-type DSL filters, high quality modem-to-wallsocket cables and short ones too, mains interference filtering. Going further, better modem or even shortening the run of internal wiring inside the house from the outside to the master socket by getting it moved, which would cost money and possibly be very inconvenient (or quite the reverse!). But on a line as good as yours, your signal will be strong so these kind of measures are much less likely to give you anything compared to the effect on someone like me with a 4.55 mile long [!] phone line and hence incredibly weak signal that is therefore very vulnerable to local noise sources which relatively will appear really loud. But crosstalk is going to be a big problem for you as for all FTTC users who do not have vectoring (anti-crosstalk systems).
Could you remind me of the sync speeds now and then?
