To be honest fencing is fecking expensive whatever you do - though am guessing yours maybe pricier due to how long it is...Maybe get some bog standard fencing guys round to find out what concrete posts/wooden fencing would cost - if it would be £9K then suddenly £11K doesn't sound so ahem!
Our fence is v ricketty - but have just secured the back and bottom 1/4 for now to keep the dog in. That cost £2k. I did dull concrete post gavel boards for security across the bottom and because it is 300 feet from the house so I cannot see it. Down the side by the planned veggie patch/chickens - well when we get round to it - have just done 4 foot high green chainlink. Privacy down there not an issue - just to keep dog in. Just another 250 feet to go which will matter so much....ouch....
Hedging? Trellis? We are using this guy (know he is not your area) as he did a lovely landscape on my in-laws - but there are a few images which may give you inspiration. I do pragmatic (fencing course suggestions) Not pretty. www.greenroomgardening.co.uk/garden-fencing
Hmm yes you see it does have to be pretty... But thanks for the suggestions. The existing fence is in pretty good nick and not too hideous, but it's too low to keep the cats in and I'm worried about them getting round to the main road. So I need something that is tall or pointy. And pretty. A good thick yew hedge would be perfect but would take so long to grow the cats would have expired by natural causes long before it was dense enough.
I think we probably will end up doing something like trellis along the top for the most part. The trickiest bit is between the drive and the house, and a temporary fence while a hedge grows could be the answer there.
Pannacotta I'm impressed by the Jackson's site - none of their fences are right for my current purposes but that's definitely one to bookmark. I hadn't really considered ready-made willow hurdles as I have yet to find a good handyman round here, and it's important the fence is done properly so it doesn't blow down in the first storm, but if I can find someone good then that could be the solution. It would be a LOT cheaper than the made-on-site stuff. And the site you linked to looked like good quality stuff - I've see a lot of bad ready-made willow hurdles but those do look good.
So perhaps my priority is to find a good handyman...
Much to mull over, thank you for all these suggestions.
Rhubarb you might be better off asking a good local landscaper or a fencing specialist, IME (and we have replaced well over 50m of fencing in total since we bought our house!) is that these are better options than using a general builder/handymen.