I'm honestly not sure how else to explain the real world drop from 50mbit to 25mbit. This is over an ethernet cable plugged directly into the router. This is also a real world figure that's significantly higher than the router reported line speed.
The only other explanation as far as I can tell is that this router is just delivering a much lower speed. But it's rated for 1gbit and is a fairly high end tp-link router. Unless I've somehow configured the router wrong in a way that would somehow limit speed I'm not sure what else to look into?
Have you still got a BT hub you could connect to see what sync speed that gives?
All I can suggest is see if you can borrow a BT hub or other router to try. If what the router is reporting is accurate, a DLM reset will do nothing.
I'll see if I can find one somewhere I suppose! I appreciate all of the help.
Does anything here look wrong:
You could try setting DSL Annex type to Annex B to see if that makes any difference.
Annex A is correct anyway, just something to try.
The username is normally
bthomehub@btbroadband.com
Enter your phone number and post results. Delete number when posting
https://www.broadbandchecker.btwholesale.com/#/ADSL