Finally managed to get the upgrade to Fibre 900. They either fixed the database issue or changed something at the exchange as the max available was 330 until I checked again yesterday. Gave them a call, told the best they could do was £67 per month. Called again, this time to cancel (was out of contract), was offered it for £55pm, which is a fiver cheaper than I was paying for the 300 package.
Upgrade went live overnight, wired speed tests seems to top out around the 500-600Mbps range. Upload speed is excellent though. I know technically you should get the max speed straight away but did anyone find their speeds improved over time?
My 150Mb went ahead last Friday and was instantly max speeds. I then noticed the 900Mb option on My BT so went ahead for that. Went live last night, i've clocked around 850Mb directly to router by ethernet.
From what i've read on Bt forums, there is no DLM or training period, you should instantly have whatever your line is capable of.