Never done Iceland Mike (only 12 volts

) but, loads of wading, in particular competitions where the water is coming in through the heater grill below the windscreen in a Land Rover Discovery. There is no way IMO that a standard LC will be safe to the door handles, the standard height for the LC GB/TB/DL breathers is at the top of the bell housing, and the engine intake at the height of the inner wing, so at the door handles you are pushing your luck. Door rubbers will invariably let water in if they are exposed too long as will seams/pipe access (heater pipes under drivers seat is a classic water entry point), so think anything over the height of the wheels is pushing your luck. Of course a suspension lift/bigger wheels will help if you have them?
So from an experience point of view, remove the carpets before you go and throw some old sacks and rubber mats in there. The rubber keeps the water off the sacking most of the time, when the sacking gets wet either dry it out if you have time or throw it away and put in fresh lot, this stops water finding it's way into the little nooks and crannies where it will take ages to dry out.
Fit your recovery straps (F & R) BEFORE you enter the river, use the rad blind you have (show off) to stop debris blocking the rad fins. Tie the fan with a zip tie to the shroud unless electric so it cannot rotate, the cold water will keep the engine cool. Ensure axle breathers are clear, the little flaps tend to seize either open or closed and neither of those positions is good, the rear one is in a chassis box section and not particularly that high up. Depending how adventurous you plan on getting you could remove the door cards as well, if you get that deep and water gets inside then once wet they delaminate and fall apart a couple of months later.
Hope I am not giving the impression I have done a lot of this stuff?
Showing off now in my Discovery, last lap before taking first prize at the SOL ROAD challenge at the Land Rover Site in Lorca Murcia 08/2011, water is 'only' about a metre deep!
Regards
Dave