I looked into Libre Fighting some time back and ended up purchasing the DVD set.
I'm still on the fence as to Unless You are the Attacker how useful some of this stuff is. I've looked at tonnes or real CCTV footage of Knife attacks and there is nothing fancy or anything related to fine learned motor skills - it all seems to be FMV ( f###### Massive Violence ) gross skills involving the attacker latching on and then repeatedly 'sewing machine' attack - unless you have a proven way to defend at that at really really close ranges from what most likely is a covert attack I think you're pretty much screwed.
On FB look at 'Libre Fighting' and for more real world ( quite graphic ) applications at both ends - 'Eds Manifesto'
Best defence against a Knife I reckon is being no where near it.
I think if you have access to someone that is willing to 'knife' spar with Big Thick Red Marker Pens and White T-shirts the lessons learned in terms of distancing and reach may well serve you well.
Libre Fighting actually Have a chapter in London http://www.librefightinglondon.co.uk/