I am in the middle of putting my dash back together again right now, after taking it apart probably halfway to accessing the heater core. I had to spend hours taking it apart JUST to access the foot/defrost flapper to un-stick it. I printed the step-by-step instructions supplied in the Roverparts kit, and followed them until I got to the flapper box. I WOULD NOT attempt this without the instructions. Yes, it’s do-able, but give yourself LOTS of time, and be prepared for lots of swearing and AMAZEMENT that a heater/fan could be buried so deep, and require so many hours of labor for a replaceable item, and at the amount of cheap plastic in what was once the pinnacle of SUV luxury. Once you lift the dash and disconnect the flex hoses to the defrost vents (I am not convinced that lifting the dash off is NOT necessary), ABANDON ALL HOPE of ever getting the hoses re-attached to the outlets. The PO that replaced the heater in mine (that’s the reason I bought it; this job had already been done) abandoned that effort and left each hose un-connected. Amazing that I got any real defrost action at all. I wriggled my hands into each location and connected the hose to the outlet by closing the ½-inch-too-short distance with that aluminum aircraft tape. It should work better than leaving the mis-aligned gap.
Oh, and I had to take a plunge-cutter and cut off an un-necessary piece of plastic on the right side of the lower dash surround, because Land Rover cleverly designed it to have to move laterally over the footwell heater duct, at the same time that it had to move fore/aft over the 1”-long stud it attached to. Piss-poor design all around. The left side uses a simple screw into a clip-nut. Why didn’t they think of that for the right side? Expect to crack the flimsy lower surround either as you remove it, or attempt to re-install it.
Sorry, had to vent, just did this last night. If the heater needs to be fixed it needs to be fixed, just be careful, patient, or pay someone to do it if you have the cash. NOT fun.