OK this is embarrassing... I am unable to access WebmasterWorld.com from any browser or PC on my LAN. It was OK yesterday. I don't have a problem accessing any other website that I am aware of. I've tried changing DNS servers. Rebooted router / assigned new external IP address (I was expecting this to fix it / unblock me, but it didnt.). Cleared browser cache and cookies, tried browser privacy mode.
I am currently accessing this on my phone / mobile network, which is OK (but awkward). I can also access the site OK via a proxy.
So, it's either me or my ISP?!
What next?! Anything else I can try?