The water is always coming from somewhere, it's a matter of taking the time to find the source(s) and fixing it.
I worked my way around the door eliminating leaks one by one. I found:
-badly fitting door seal around the top
-Perished seal between windscreen frame and bulkhead
-Badly fitting vent flap seal resulting in the formation of Lake Dashboard
-Kink in the door seal on the curved section
-Hole in the floor as a result of the leaks
-Some water coming in around the door bottom seal strip.
Now, apart from the last one which lets in a bit of water in heavy rain (work in progress) the leaks have stopped

I did get some funny looks sitting out there in the rain though.
Yes, most land rovers do leak, but they don't leak because they're supposed to, they leak because something isn't right. The trouble is they don't get fixed because 'all land rovers leak'.