Stand the kettle upside down. Remove the three screws in the base and remove the plastic kettle base.
Inside there are three springs between the outer aluminium case and the inside assembley. Remove these with snipe-nosed pliers.
The inner will now wobble. You now have to pull the aluminium outer upwards from the innner, but also you need to push on the water
gauge glass so that it will tuck inside the outer. Press it inwards at it's top and ease the outer up over it.
I guess the leak will be round the lower seal of the water gauge. Clean this up with descaler if needed. There are two plastic seals,
I put a touch of WRc accepted silicon grease on top and bottom of each of these.
Reassemble the kettle making sure the water gauge engages in it's slot and test it.
Tony Meacock, January 2009