Slow Fibre Broadband
I'm on Unlimited Fibre 30-41 Mb and having problems. Speed tests are variable, currently averaging around 27 Mb. This should be ok, but I'm regularly finding that it takes an age to open a web page or I get ' 
This site can't be reached' and downloading large files can take forever/fail. It feels as though the speed is there but the internet connection is very weak - is that possible?
I wonder if this is because of Coronavirus increasing demand? Though my neighbour (on BT) says his is fine. I don't have lots of web pages open and although there are two of us in the house, we take care not to make heavy use simultaneously.
I've tried ringing Plusnet but their wait times were 40 minutes yesterday and they aren't taking calls today (understandably in the circs).
I considered upgrading to Unlimited Fibre Extra, but this only promises 30-47 Mb and I don't want to be tied in for another 18 months if the extra cost only gets me a few more Mbs.
Any suggestions please?