i had a go at this on sunday, pulled the complete dash out (top and bottom) and dropped the steering column down so i could drill out the 40 or so spot welds in each vent blank. The defender dash and vents bolts pretty much straight in with little fuss. im going to have to make up some hinges to pop rivit on the firewall and stick some mesh in the holes to stop bugs flying in but all up turned out a pretty simple comversion.
While i was at it i changed the steering column for a defender one so i could have the defender style steering wheel. to remove this i unbolted it and had to cut off a bracing tab to fit it through the firewall without removing the brake booster. its a tight jiggle but it did eventually fit.
On the downside i busted my winscreen removing one of the vent blanks
