Hello all, I am a newby and about to buy my first narrow boat and would be very grateful if anyone could help with the following two questions. The boat I like has a toilet holding tank with the pump out connection mounted on the cabin roof, all the other boats I have looked at seem to have them on the gunnals. Do they work ok on the cabin roof with having such a long suction down to the tank ??? Also I have read on the forum about self pump out kits, is the suction of these pumps fitted into the normal pump out point on the boat or are do they require their own separate connection directly into the holding tank ??? Any info would be very much appreciated. Many thanks.