Then you have a problem - I read your original question regarding this area. Anything you plant will need watering initially and regularly throughout the spring and summer when its dry, or it'll just die. The best option is probably to wait until autumn, having decided what you'll plant, plant up and let them take care of themselves over winter, when they will hopefully have enough moisture to put out new roots, but without water during dry spells, shrubby plants like prostrate junipers and Cotoneaster Queen of Carpets will need to be watered when its hot and dry during the first year or two. Smaller ground covers such as Helianthemums will also expire on a hot, dry bank if it stays dry for a long time. The problem with water supply might explain why there's nothing growing on the bank already apart from bulbs and opportunistic weeds.

Tercol, when answering the comments to a question, you should post it in the box underneath the comments on your original question. That way those who answered will see your reply.

We put the bank there as there will probably be housing going on there and we feel it will help give us privacy we have a flat walking area on the bank top of approx 4ft width which if need be we will plant with shrubs, in the autumn we planted loads of daffs and were advised wait till spring! Hence the request

Hi Tercol, are you sure on your dimensions - you're talking about the best part of half a mile at 750 yards.
At that sort of length of bank you might just want to think of something like grass with a meadow mix of annuals that you just strim once a year.
You were asking about hedging for the top of the bank before, this amount of space and slope would seem to be crying out to be left as natural and low-maintenance as possible.

Crikey, who told you to wait till Spring!? Best time for planting permanent things like shrubs and perennials is actually autumn, with a few exceptions (Ceanothus, Garry elliptica for example).

Yes sure of length bank is too far and too steep to grass and trim hence want some form of groundcover, the only reason we will plant on top is if building goes up beyond the boundary

For a hedge along the top if necessary: Blackthorn will grow in that position - it does in our garden. It has dainty white blossom, sloes if you're lucky and is the very devil to trim as its so very thorny. Makes a burglarproof barrier though. It does send out runners but in that position it probably wouldn't matter.

Whatever you decide to plant for groundcover you could try mixing a good amount of water retaining gel into the planting holes (make them extra deep and then fill in again to the required depth) and water the plant really well in. This made a life saving difference to some perennial geraniums I had on a very dry shady site. Just try it with a few plants for starters and see how it works in dry weather before splurging on a lot. Native navelworts (umbilicus rupestris) will grow too, though they disappear in winter,and native stonecrops will survive depending on soil, though both of these are pretty small.. Which direction is the side of the bank
that faces you, ie full sun or lots of shade?
And had you thought of winter flowering heathers? They grow into big clumps that exclude weeds very effectively.