Target SNR margin reset

[#1]

You are on 21CN (confirmed by the BT tester doing an upload test) but for your attenuation (line length), as you will see from the Internode graph on this page there is no benefit from connecting with ADSL2 rather than ADSL1 (G.DMT). In fact the DLM sometimes causes ADSL2 to perform less well than ADSL1.
In my opinion staying with ADSL1 (G.DMT) is the best option.

[#2]

Thank you. The inter mode graph puts things into context nicely, very helpful. I'll just see how things go from now.