@andytay just for future reference the dyn.plus.net part that you have also quoted is your IP address in reverse, so the first octet of that is actually the last octet of the actual IP address.
Now an interesting thing about that IP address range (which I haven't seen before) is that various geolocation puts it in the US, which means details have not been updated to show that it is Plusnet. This could give you problems accessing a number of websites. Can you post the IP address details in this thread
Next, out of interest can you check Which Gateway you are on, also open a command window and do
tracert -w 1000 ntp.plus.net
Having done all that, then login to your Technicolor and under Internet Connection in the Internet Box click on the Disconnect button - this will drop your PPP session to Plusnet. Wait 30 seconds and then click Connect.
Repeat the IP address, Gateway and tracert checks.
As far as the BT Speedtest result goes, you can ignore the red downstream for now, that seems to be related to the fact it thinks that the acceptable range has a minimum of 40Mbps (for whatever reason) the actual result is consistent with the IP Profile. What is of concern is the Upstream speed - well below par.
Repeat the test since you've done the Disconnect/Connect (hopefully different IP address range) and see if it's any better. Also run the TBB Speedtest and also speedtest.net and post results from all 3 for comparison.
