Vice grips. No jokes.
I used them to remove almost all of my OE hose clips. It can be a bit fiddly clamping them on, but once they're on you can wiggle the clip off the section of pipe that's over the flange and then pull the hose off easily. Tenner or less from almost any hardware/tool shop, B&Q/Homebase etc and they're a great bit of kit to have handy if you don't have some already. Since buying mine I use them all the time!
If you can't get at the clip from the top, get the front up on axle stands, undo the bottom of the front bumper and try and get access from there. Not the best picture... but.. here's me removing part of the bottom rad hose with them from the top.
Also if you're removing the hose entirely, you might have trouble with the bottom hose where it's held in place, bottom centre of the rad. Just keep spinning the bolt slowly with a socket set, while applying some upward pulling force and it will come out. Don't use a ratchet spanner like me!
In case it's of any use to you, my post from when I changed my coolant and hoses is in my project thread here:
http://www.cliosport.net/threads/my-ff-bg-182-picture-heavy.705220/page-2#post-10393366
