I have a box of about 300 x 5 mm dia high tensile self tapping screws with POZIDRIVE heads. These 20 mm long screws are used in the construction industry for attaching sheet metal to steel purlins.
However they are excellent for securing floor panels and any other accessories or brackets in your Land Rover or your off road trailer where you want a detachable fastener. They are vastly superior to the original OEM slotted screws used for example in Series vehicles as they don't corrode easily.
Will swop for a bottle of Scotch.