Gary is perfectly right about having a garden which is wildlife friendly. The more you encourage birds, insects, small mammals etc. the more you will benefit from healthy plants and a healthy environment for wildlife. Although your garden is small, can you designate a small area as a wild area? I'm lucky to have a large garden and the bottom of it is kept as a wildlife area. The grass is only cut twice a year and I leave the flowers (weeds) to do their own thing. I have put bluebells, honesty, vinca, daffs, snowdrops and other stuff there but I never destroy the nettles.
I love nettles, such a versatile plant. The young leaves are used to replace spinach in cooking and the older leaves - after the butterflies have done their thing - are used to make nettle manure. I have an old dustbin into which I put the nettles and rainwater and after a couple of weeks sieve and decant the smelly liquid into old plastic bottles which I leave by the water butt and chuck a glug into the watering can to feed the toms, peppers etc on the veggie plot (about 1 to 10 ratio). When my children were approaching puberty I used to give them nettle tea twice a day and none of them suffered with acne.
They say nettles cure rheumatism. Well, I get stung regularly out in the garden and I've never had rheumatism so maybe it's a deterrent too - mind you, the itching drives me mad at night. Perhaps someone knows how to stop the itching after the sting.