Grit spatter on legs - what to do about it?

The last couple of weeks in Perth have been fairly wet. I've been
rained on quite hard, but the sand and other crap I get spattered with
matters more.

I've ordered some mudguards from eBay for the front and back wheel,
but a friend who used to live in the UK says bike shops over there
often sell plastic leg protectors to be worn specifically to try to
shield the legs from all that muck.

My current strategy is just to take a full change of clothes including
extra shoes to uni but if these leggings are any good that would save
some weight, plus I'd rather not get spattered in the first place
because it's really hard to quickly clean my legs up in the men's
bathroom and I'm never entirely grit-free when I put on my pants.

I really hope the mudguards will make a large difference, but my
experience with mudguards (my road bike has a seatpost fender)
indicates that they only provide modest protection and one way or
another I'm still going to get wet sandy shoes.

What solutions do you guys use?