Hello happywellies, i can sympathise with you, cats can be a real problem sometimes, what about planting a few heathers that flower at different times of the year and create a carpet of colour, once established trim after flowering to stop them getting leggy by doing so you can get that lovely cushion effect, check your soil if you go for heathers if need be dig a lot of ericacious compost in and if you can get hold of any, then dig in old pine needles, or you could use some ground cover cotoneaster, or ceanothus, or hypericum rose of sharron, There used to be something you could buy to keep foxes and cats out of gardens, i think it was called Renodene.

"Renardine" is a fox repellent, but I've just read that it's been banned. I hear lion poo works well, but you may not want to replace one poo with another.
Cotoneaster horizontalis came to my mind as a spikey ground cover too. Ground cover roses could make the area a bit prettier.

There's a useful website here -
http://www.cat-repellant.info/index.html
with some home remedies. I hope they work for you.

Periwinkle could do the trick... heathers will take a while to form a complete covering and would need to be cut back regularly. If you click on the 'G' below and then on 'Ground Cover Plants' you might get some ideas.

I have the same problem, and I end up putting flower pots or large rocks wherever there is a patch without a plant. You could also try sprinkling pepper dust, or garlic.

A few of my customers have cat problems and some cats actually poo on top of the heather foliage!

Make any bare soil areas spikey and uncomfortable with cocktail sticks or trimmings from rose bushes. My dad never threw rose trimmings away - he always had a place in the garden in mind for their positioning and even with cats living each side of us we soon stopped having any problems. :o)

Marigolds are unpleasant smelling for many pests, including cats. Put a border of them around the bed and it will both look nice and keep them from using your garden as a loo.

Eryngiums are both spiky and very attractive, you could also try planting thoses.

If this fails, they you could plant lillies, which are toxic to cats. That will not keep your neighbour happy, but then again she is not being very neighbourly by letting the cats pest you. The cats will then think twice about going near your garden again.

"she is not being very neighbourly by letting the cats pest you"
I do sympathise with the neighbour too here - there's not much that she can do.

Would a shallow arch of chicken wire over the flower bed with plants growing through it be possible?

One good ground cover plant you could try is Ajuga reptans . . the most common has purple/brown leaves, (more attractive than that sounds!) and there's another with multicoloured leaves. They are low-growing and have blue flowers. Your idea of covering with netting while they grow sounds a good one. Good luck.

Well, well, just answered this on the other site, Happywellies! I recommended Ajuga as one of them, as Sheila does above, but I did forget to say something - if the neighbour's cats are tom cats, they may well continue to poo there, but on top of your plants, as Anchorman mentions. It's very unusual for she cats to do this, but lazy old toms, specially un neutered ones, don't care...If that happens, the only recourse is lots of short sticks stuck upright into the soil.

OUCH!!!!!!!!!

Hee hee, I guess you're identifying with the lazy old tom cat then, Littlelegs, lol...

Thank you everyone for this. There are some really great ideas here. I really do appreciate all your help. It's my first time to join a gardening website and ask questions - so apologies for the double post. It's a great day today, so I'm off to investigate the plant suggestions and do a bit of gardening. I'll let you know how things progress!
Thank you - it's a great feeling to link up with gardeners who know their stuff.