Imgur loading very slowly with Plusnet?

[#1]

I have plusnet Unlimited Fibre broadband however imgur links specifically seem to load incredibly slowly (56kb/s slow). I have noticed that this slowness dissapears when entering htpps:// instead of the default http:// before the URL. I think the issue may be something to do with Internet Watch Foundation (IWF) filters but I'm not 100%. Would a VPN such as PIA fix this? Is there anyway to always direct to the https:// version of imgur? Anyone else having the same issue?

[#2]

Can you provide an example link which exhibits the issue?

I randomly googled a imgur link and http links seems to load as fast as https.

Have you checked your plusnet safeguard settings?

Perhaps turn it off temporarily to confirm whether it is the cause.

fwiw, if you wish to test any VPN to see if it would make any difference, protonvpn offer free VPN plan for 3 of their servers: USA, Netherlands and Japan.  Not UK.  There may be restrictions.  As far as I can recall, they don't ask for any payment card details for signing up to the free plan, unlike PIA etc.

[#3]

I'm not seeing any sluggish behaviour in accessing imagur - but then I always use https.
The slowness could be a re-direct from http to https, as that is what happens when you go to Imgur.

https should always be the preferred option and as you end up there anyway not just start with it?