removing front wheel - tools required ?

[darrsi]

job done
was easier than i thought and didn't need to remove the calipers
looks like the old sensor (the bit with 2 lugs) was at fault as both were  sheered off.
all replaced now and works (but no test ride yet).
thanks for your help all

Just remember those lugs in the future, because it will let you put the wheel on even if they're not seated properly, but they obviously just snap as soon as you tighten the wheel nut.