Why not have a look after removing the nettles might be some good compost?

If the nettles are growing in a compost heap, they should be fairly easy to dig out, even though they are deep rooting. Get rid of the pernicious weeds like the nettles and use the compost, if it's useable, as Drc says.

You could try covering them with cheap tarpaulins (from B & Q) I'm not advertising, others places may have them too. Then in Spring the nettles will come away easily then if the compost looks viable, spread it. Lovely. Its a gift.

if you have nettles then the compost will be fine proberly fine enough for seeds or cutings, good stuff.

Great, thanks guys, it does looks like good stuff, just got it into my head you shouldn't spread anything around that might have perennial weed seeds in it. Will get rid of the nettles and see what I've got to work with, if its good stuff, it'll be a real bonus!

If its been sitting untended for that long, it will have weed seeds in it, unavoidable. Just be rigorous when they germinate.

I was told by an old timer that nettles make great plant food, but that any viable roots soon take hold.
His solution was to pull the plants up & put them in buckets of water for 3 or 4 weeks. He then used the 'nettle tea' for watering.
It may just be an old wives tale, but I always used to get good results on my veg patch, especially with courgettes & french beans.

Nettle tea is very god for veggie as is comfrey tea. Just don't put flowering nettles in the bucket.

the soil under a nettle bed is allways fine