I have had a few 2.2 engines ones and some have had some nasty backlash from the rear diff when pulling away and changing gear sometimes, not had it on the older ones , I have gone back to a 300TDI which in my opinion is the best Defender they...
if you are dexterous enough you can do it through the ashtray hole rather than removing the whole dash top. But if you are replacing I would advocate for mounting spray bars on the wipers and fitting a y-piece in the washer hose and feeding out...