Yes - this is the problem with storing a Stalwart outddors and without any cover over the whole vehicle. The air intake is immediately behind the cab, full width by 6 to 8 inches wide and feeds straight into the hull and onto the fuel and oil tanks. Air outlet between the two rear tailgates feeds straight down onto what would normally be the front of the engine and the radiators. A few years of rainwater collection at these points starts equalling heft bills - UNLESS - the hull bilge plugs are out and allowing it to drain away.....
Can you get a crafy look at the Mk 1 to see of the bilge plugs are undone?? If they are then you're in with a fighting chance; if not then look elsewhere.... Wheel stations aren't that hard to fix (so I'm told by those who know), it's just the sheer size of the parts involved and the complexity of the seals and Tracta shafts/joins.
Getting back onto the Ferret s of the ooriginal topic - there's a Mk 2 on Milweb today, "Unrestored, stuck engine, very good rebuild project, most parts present. Pre 1960" - no price given if anyones interested!