how would you kill off this grass and return it back to something better looking?

Turn it into a wild flower meadow. Then you could just strim it after flowering and they'd just grow again next year. It would take a lot of maintenance if you try to make it too formal.

This will require manual labor - you knew it was coming didn't you? Do you have a spading fork? They work really well in getting out those clumps or grass. Think of it as a two-step process; as you remove those clods of grass, you'll also be tilling the ground - a necessary step anyway for new planting. Avoid using herbicide if you want to save those nice hydrangeas and/or plant something else. I'd recommend a low maintenance ground cover; vinca minor, solomon's seal, ground Ivy or such like.

You might want to consider Crown Vetch too.

Sorry Bathgate don't agree about the Vinca minor, boring plant that can take over! Ditto ground ivy.
Wild flower meadows are hard work too, not just a matter of chucking a few seeds down.
I would suggest going to the bottom of this page and under 's' seeing the photo's and suggestions for a sloping garden. They can look stunning and some people would die (figure of speech!) for a change of level in a garden!
You could do a little bit at a time, take the top layer of grass off, dig and add some enrichment and plant a shrub or perennial and mulch in between. Layers of newspapers with bark on top work.

Honeysuckle If they don't like vinca or ivy, they can find something THEY find appealing. That's why I added "such like" to the end of my statement. The Hydrangeas that are there already should be the focal point. Wild flowers will look ok for about a week or two. I was suggesting a ground cover that is tough, attractive, weed smothering and low maintenance.

Layers of Newspaper looks like so much garbage blowing around like inner city ghetto look - not what I was going for. It also disintegrates quickly, cats scratch and pee. Weeds will grow on top of the newspaper when it gets wet.

You can put down a weed barrier, then mulch on top of that. Don't use newspaper.

Grass is probably the best ground cover of all, just keep it to a manageable length with a small strimmer - a battery one makes it easy.

This is not my place im volunteering near biarritz france and i took these photos to get some response on what i find is a difficult situation for the owner.The ground is very stony and clay compacted and large rocks have been inserted to stabilize the ground so digging out the grass would be a painful experience even cutting it short is difficult because of boulders and shrubs and balancing up there and strimming it has already done my back in so im on a sick day today. i think that just cutting the grass back is the only solution as any mulch will end up sliding down with rain and membrane will look naff without something covering it and planting something else will require clearing and digging it the grass could be groomed i guess to get the dead out of it then seeded with more grass i think THIS IS A JOB FOR SUPERMAN!

No, it's a job for a landscaping service.

If only the owner wasnt so adverse to spending money yes she could do that but while theirs twits like me to volunteer for free why should she?

You seem very miserable about this whole project. So why bother?

thats true! the volunteering gets me down sometimes

I hope you have help. This is much too much for one person. You also want it to reflect well on you.

Don't let it get you down, you are kind to do it.

I suggested turf terracing on your other version of the question - and now that you say it's in Biarritz I'd still go with that as it's very 'French' - think of the Ballroom Grove at Versailles (with box? hedging along the front of the steps)