Gabriella, I believe the August upgrade at the exchange is complete and whilst the upgrade to the Infinity product is scheduled for December 2010, neither the duration of the works nor a completion date is indicated.

By calculation for my line, the synchronisation speed, attenuation and signal to noise ratio margin figures show that a throughput speed that lies in range between 12.5 and 14.1 mbps is achievable on an upto 20mbps service.

These values matched what BT estimated as being deliverable. It is only in the the post upgrade period that the test figures on BT's system have been hurriedly downgraded across the exchange.

Given that previously I could achieve 5.7 (+/- 0.6) mbps on an uptp 8mbps service, an increase of around 1mbps does not represent any improvement that could be classed as significant.

The questions of how or why these estimates in the BT system have been downgraded and why the actual performance figures remain so low have not been answered by BT.