In the first instance I would buy/borrow/hire/get a man with a petrol strimmer fitted with a brush cutter head and cut it all down hard to the ground and clear the rubbish away. Then loosen up as much of ther ground as possible and get your wild flower seeds down. The nettles and such like will keep coming back but short of repeated use of weedkiller which would also kill the wild flowers there is probably not a lot else that you can do. A buddleja bush in the nettle area may help to suppress them.

Honey bees can't use buddleia unfortunately as their tongues aren't long enough, but buddleia globosa with the round orange flowers is ok for them.
Much though I hate to spray, I would definitely recommend that you glyphosate the area once or twice before cutting down what is left. I have a lot of experience now in trying to clear 'scrub' and having not used chemicals at all, now very much regret it. By killing off the worst of the perennial weeds you will make the situation easier to manage in the long term. Nettles are fairly easy to kill off with glyphosate.
I'd recommend phacelia which is a great bee plant and will go on self seeding for years, as well as other wild flowers and perennial salvias.

I'd second that - cutting them isn't effective. Its easier to dig them out in winter as the roots are bright yellow and easy to see, but if time is short and you don't want to use chemicals you could go down the brush cutter route and then cover the whole area with heavy black plastic for a whole growing season. This will finish most things but if anything does come back it will be much easier to get out.
Nettles are great fertilizers so the resulting soil may not be the best for smaller wild flowers but phacelia, scabious (unless your soil is acid), foxgloves, and how about some honeysuckle? Sprinkle some wild poppy seeds, English and Welsh, and some corn cockle (PM me in the autumn if you need seed of that). And how about some English bluebells, which will bloom before the other stuff gets going? Wild roses on the fence would be nice too.

You could have an elder as well if you don't mind the seedlings - the flowers make nice refreshing tea!

Sounds like my 20 pole allotment when I first became its tenant/curator/lover ! You forgot to mention Couch Grass. I dug all these roots out with a border fork. Took me 4 years ! I knew it was good ground because the plot next to it is lovely soil
I would advise to follow Bulbaholic's advice. If you have the seperate Wheelie Bin for garden recycling, it will be easy to just dump all these roots (without soil lumps) into it, for local council removal. I dumped all mine in a corner of the allotment to rot.
Then dig out the roots gradually with a border fork, when you have time.
I still find Bramble roots in the area I paid a man to clear 2 years ago. They penetrate a metre. Keep at it !
I have now found that Tansy is a good root matting weed control plant.
I have an area against the fence at the top of my garden
beyond my Patio Roses, here behind the flat. During this wet spell have divided clumps of Tansy plants and replanted here. They will spread in 2 years and cover any weed growth, also keep the Greenfly off my Roses, saving the cost of sprays. When you have cleared one area, try your Wild Flower Seeds - Google
The Wild Flower Trust website up in Liverpool. Lots of good advice here.

Once again guys, a heartfelt thanks,as a reluctant gardener the support on this site is very motivating.
as i can easily find reasons avoid these tasks.Jamesmac

Hello again James, no one has mentioned the Rotovation Route. When you have had the top growth cut down and removed/burned (if the neighbours dont mind) or cleared away in your Council Wheelie Bin, and the weather is dry for 9 weeks, the whole garden can be rotovated. This cuts up the weed roots, particularly Couch Grass, but every piece grows.
Rotovators can be hired. It just needs a settled hot weather period, then you can Rotovate it to turn the cut up weed roots to the top again for the hot sun to dry up.
As it doesnt seem likely this will occur this year, I would go down the digging by hand route, but covering the area with black plastic/old carpets.
As you progress, move these back. It will encourage you to carry on while the weather is warm, exposing the soil which is ready to plant/sow.
This is what I did. I had crops off my plot the first year I had it.
The National Wild Flower Centre is at Alderhey, Liverpool.
They sent me information, recommending that Wild Flower seeds germinate more easily in poor soil, so I used old potting soil.