The engineer didnt appear to do anything to the master-socket bar plug the lead in which goes to the BT modem
What sort of master socket do you have? if it just has one socket for the phone line and it is that he plugged into the openreach modem then the install was the same as mine which is incorrect.
A different Openreach engineer turned up today to sort mine out and like the Sky Fibre team was shocked by the original install, in his words "this type of thing gives us a bad name".
So he installed a new faceplate and connected up the openreach modem properly. The router stats now show I'm connected at 74604 compared to the previous 56000 and speedtests average around 66Mb/s which is 13 meg better.
I was happy with the speed before but if engineers are just plugging normal phone lines into the openreach modems then they are doing it incorrect and cutting corners.