Simon Mogridge wrote:
A leaking kettle has damage the newly installed laminated chipboard
worktop in my kitchen. A raised area/blister approx 8 x 3cm and 1mm
high has appeared at the butt joint. As you might guess, the joint
lies over the edges of two carcases and the application of a clamp is
impossible. Can anyone please tell me how i can remove the blister
and re-seal the joint with out major damage. The replacement of the
worktop is a non-starter, i just could not face it after taking such a
long time to complete the kitchen!

You have a problem.

If you can get to the back of the worktop, then carefully removing all
of the chipboard in the area of the blister, without going through the
surface.
Now, fill.
Every time you put kitchen units or worktops in, I'd strongly recommend
coating the edges with several coats of an exterior oil-based waterproofer.

This will mean that it won't suck water up like a sponge.

Do you have a spare bit of the worktop?
You might try various fixes on it.
I'd try setting an iron on 130-150C, and pressing it on for half an hour.