Kolibear
Thanks. It was reading that article that triggered me off to get something done about this in the first place!
Our engineer has made an interesting discovery. This Warrior was originally fitted with air con. (I wished it still was during the 'summer'). When it was removed the vents and some of the ducting were left in place. It may be that water is entering the rear fuselage and running forward just like that Cessna. This may be the water we have seen running from the drains after taxying, trapped behind stringers in the tailcone.
I'll report back.
David