I had the heater matrix fail on mine in the same catastrophic way, just glad I had my work boots on!

As for doing the job, I followed most of the detailed job from the Rangerovers.net website, except I didn't remove the dash top. I stripped out the drivers side under dash area and cut through the steel frame on the dash to get it to clear the matrix and out it came. Easy as!

Just riveted the frame back together when I reassembled it.

Been a month now, no leaks! Fingers crossed.