how easy is it to fit diffrent seats?

Hi all how easy is it to fit seats from say a discovery or similar car to a series 3? Any tips etc
Thanks before hand

I have Disco 1 seats in my Series.

The drivers side i dropped the fuel tank out, then bolted them straight down to the seat box.

The passenger side is slightly harder. I decided i wanted easy access to the under seat area (I keep batteries in mine) so cut a section out at the front of the seat box. I have since seen some very neat side cut outs with hatches which i would probably favour.
I then bolted the seat to a sheet of metal then bolted the sheet of metal down over the the seat box (using the hatch where requried to access under the seat)

I am sure there are beter ways of doing it, but, that was my method when i first bought the Series and didn't have much experience of making stuff. I think that a secure but quick release mechanism for the passenger seat would be better and not hard to implement.

Cheers mate ended up buying some from exmoor dead easy to fit cheers tho