first submit your upgrade request here**: https://www.idnet.net/support/guides/basics/adsl2plus.php
** i dont know if it's possible but adsl2 is better for you than adsl2+. but they might offer just adsl2+ which is worth trying.
The OP's (Stevie1978) exchange is not enabled for 21CN WBC services and there is no presence for LLU. ADSL2+ is not going to be available for ANY ISP - the best he can get is ADSL (G.DMT modulation).
if its not a hassle you can show me the pages in the advanced and if its too easy then the rest of the pages in the router to be done with it xd
There's nothing really in the advanced settings that is going to "optimise" his connection, at least in relation to his connection between the modem and the exchange.
As for firewall and UPnP, I would
strongly recommend the former is enabled and that the latter is disabled in situations where it is not needed as it tends to have security implications.
The max MTU on the mass of Billion devices is 1492 bytes, not 1500. That is the highest value you could try, but I do not know which value would work best on IPStream services (ADSL Max) and the benefit of an increased MTU in terms of throughput is generally small.
Stevie1978, perhaps you could look at
https://kitz.co.uk/adsl/btsockets.htm and identify what your socket looks like so we can better assist you in your cabling/filtering?
Also, you might want to ask mods to remove Screenshot_2018-05-20-15-47-49.png since it exposes your landline number... since I imagine your login address is based on that.