It's fine to do it like that Kerry especially as you are on light soil. If you can cover it with some Teram (the woven membrane stuff) it will stop weeds growing & the worms will be a little more active as it will act like a cloche & warm the sol a bit.
You could always leave it inplace & cut a cross in it every18" - 2ft & plant your spuds thru it in the spring if you wanted to save earthing up
