Safe Crate for Car

I'm looking for a good, crash safe car crate for our dog. She's a medium sized collie and we have a Skoda Octavia estate (with the lower boot floor, not the flat version).

Our dog usually travels in a bed in the boot and she's a very chilled traveller but we do a lot of long motorway journeys and I'd like her to be more protected in the event of a crash (god forbid). Also, I think it'll be handy to be able to pack bags up against the side of the crate rather than trying to make sure nothing can fall on her!

We intend for it to be a fairly permanent fixture in the car so it doesn't need to be particularly portable/foldable etc. The good ones do seem very expensive but I'm willing to pay if they are worth it.

I've been looking at these:
http://www.transk9.com/crash-testing/
Or these:
http://www.safedog.co.uk

Does anyone have any experience of these? Or can recommend any other types?
Cheers!