My wonderful heated front screen decided it wasn't having any of it this morning

.
I hit the front screen de-mist button expecting a rapid defrost...however
the lamps shone in all the right switches,
the air was directed to the front screen,
the rear window de-misted beautifully,
but the front screen remained ice-bound

...apart from 4 ever-increasing circles that got
bigger as the heated air did the job of the heater element
So...does anybody know where the fuse for the front screen element is located?
(My hand-book is 60 miles away and it will be cold and dark when I get home!)
Thanks