I've had Plusnet ADSL broadband for about a month, and it's fine bar one thing: we noticed pronounced slow-downs / non-rendering for Instagram and a few other FB-related apps. I know this has been covered before in the forums, but for what it's worth I found a fix which works for us.
I noticed that using my VPN solved the issue on phones and laptops, so I then experimented with switching the DNS provider on my device (obviously the default DNS server is the Plusnet router). Bingo! Instagram now loads perfectly, either with or without VPN.