STOP THE PRESS.....
Changing the MTU DID work for me.......
I followed these guidelines from the UK Playstation forum:
TO CHECK AND SEE IF ITS UR MTU SETTING!!
Have u tried, from windows command
ping -f -l 1492 www.google.com
see if the MTU is the problem with ur ISP..
If you get reply its fine. Thats not your problem
But if you get "Packet needs to be fragmented but DF set." or ERROR's
THEN lower the number, TILL you get a reply, then thats the best MTU setting.
I had mine set at standard 1492, tried a few combinations and eventually discovered 1370 was my max, set my ROUTER AND MY PS3 to MTU 1370 and it works perfect now!!
hi guys, i started getting this problem about a week ago and it is only just now that i fixed it, i tried messing around with all the settings (MTU, DNS etc) and nothing worked. i am using a belkin ADSL wireless router, and i realised i did't have the latest firmware for it. so after installing the latest firmware PSN now works like a dream again (i have no idea why it suddenly stopped with the old firmware as it was working fine for about a month)
just thought i'd post this as it may help some people, and people may have overlooked this (as i did)