The Cotoneaster that you describe is C. horizontalis (I know, badly misnamed!). It will grow flat against your fence and the bees love it. Blackbirds like the berries and this winter we had waxwings on one. See my blog from January
http://www.growsonyou.com/bulbaholic/blog/22430-waxwings

Yes cotoneaster horizontalis is a good choice, pruned corectly over time you can make it have a compact habbit against the wall, another choice could be pyracantha, nice flowers, nice berries, evergreeen. pruned properly for a compact habbit then this would be worth planting, has plenty of thorns, good for nesting blackbirds and dunocks.

As bulba has implied, if you plant cotoneaster horizontalis against a wall or fence, it will grow vertically instead of horizontally. If you are in a frivolous mood, ask for cotoneaster verticalis and watch the puzzled look on the junior member of staff's face in the Garden Centre. :-)

Thank you for these replies. There will be six fence panels. Would I need one cotoneaster horizontalis plant for each? I see what you mean about the misnomer, Bulba and I might just try the verticalis Andrew,when I go to Hilliers!
I'm a bit wary of the pyracantha in this position but like the idea and could plant a couple on the other side of the fence as I live on a corner. I'm eager to support the wildlife wherever I can.

Personally i would plant two per panel, this will enable the fencing to be screened a little quicker.

Thanks Julien. By pruning correctly did you mean cutting off anything that sticks out too far over the drive? When is the best time to prune cotoneaster? I'm always at a loss when it comes to plants that bloom and berry as it seems you have to lose one or the other!

We have Cotoneaster Horizontalis growing the full length of our back wall it's about 6ft in height it's always smothered in berries which the birds love plus we have birds nesting in it each year , we keep it trimmed by cutting off long shoots as they spring out mainly in the spring ...

Thanks Amy,
I'll follow suit! That's when I get that far--the fence isn't in yet! I can't wait to get started on the planting.

Good luck with it Penny :o))