I can't activate my iphone 4s on o2

I had to do a master reset on my iphone through itunes, due to a faded backlight that i couldnt change. I plugged it in, reset it and then left it overnight to chill out.

Turning it on this morning, its started from the initial set up. I've chosen the language and country/region, authorised my wi-fi network but now its saying "Your iphone could not be activated because the activation server is temporarily unavailable." I've tried connecting to itunes and my computer just says the same thing. I cant  contact apple customer support as they dont open on a sunday!

So any advice, tips or comments would be greatly appreciated!

Thanks