Title says it all really. help?

use a wide flat screwdriver and ease the rubber lip over the metal flange

real easy, just push the seal off along the bottom and front then should pull out.

technical section?

cheers for the help lads. didnt wanna just go straight in with a screwdriver unless i knew itd work

Never had to resort to screwdrivers myself.. Just use your foot! Start off in one corner, keep your foot fairly flat on the glass and have someone outside ready to catch it - works on windscreens too (non-bonded of course). To put them back in, lay some suitably sized wire around the seal (I think I used telephone cable for the windscreen) get someone to push the window up to the hole from outside, then gently pull the ends of the wire while continuing the pressure from the outside - the seal should just pull itself over the lip as you work your way around by pulling the wire!