In the kit car world, shower attachment pipes have been used for cabling (although it's primarily for appearance rather than shielding - but it would have the same effect).

I've seen £3 for 2m lengths on eBay:

http://cgi.ebay.co.uk/Flexible-showe...94ab44ffa69507

Although it does say £4.99 later on - which means for 10m, it would be £25. So similar to the Farnell price...