Hi and welcome to the forum.
Are the speed test using WiFi or a cable to the router. Plusnet recommend that you use a wired connection to test your speed as WiFi is unreliable.
As this is a new install could you check that Plusnet and BT Wholesale have set up your speeds correctly?
Your Plusnet line speed is hidden at this link
https://portal.plus.net/my.html?action=data_transfer_speed and requires your username and password. I would bookmark this link for future reference as it is not available by any other means.
Also get your BT Wholesale speed and profile details at
http://speedtest.btwholesale.com/PerformanceTesterWS/ .
Ignore all the text in red and just click "yes" and then "Begin test".
When that completes click on "Further Diagnostics" and then enter your telephone number on the resulting page. Then click "Run Diagnostics test" which will hopefully show you the BTW profiles as well as the results again from your speed test.
If any of these is incorrect then you need to call Plusnet or using the web chat.
If they are all correct, then just try to log onto the router, select disconnect , wait a minute or two and then connect again. After it is back on-line, recheck your speed at the BTW link above. The reason for this is that the line may have been set-up correctly after you initially turned on the router so this just makes sure that you have the most up to date connection information.
If there is still a speed issue then contact Plusnet.
Ex - Plusnet Customer (2009 - 2023) now with BT
