So, if I wait a month, the test might work properly for me as well! Thank you 
Only if you have also notified the Plusnet staff member in the link.
Though it seems to happen more frequently to Plusnet customers for some reason, it also can and does happen to any customer who's connection is BTW based , I'm with zen and it ain't working for me, also it is throttling back downstream throughput to 38mbps, it has never given reliable results