We use a Mercedes 190 petrol fuel pump (with heat shrinking on the connections) with normal fuel pipe into 25 ltr plastic barrels. This plugs into the cigar lighter of the vehicle or a battery via an adaptor. We have 'harvested' various fuel pipe unions from a local breakers yard. A bit of common sense and ingenuity usually gets the job done. Most diesels have their own in-tank pumps anyway so we just bypass the relay and pump the fuel out that way. We have done loads for the local RAC Patrols with no problems at all (except Vauxhalls that get air locked!). This is a much faster method than the 'hand pump' type. We give the fuel to a local Military Vehicle enthusiast who runs his 'Duece & a Half' truck on it. He signs for it so I can demostrate the 'waste transfer'. I can't see how any other method is safer. Petrol vehicles use an electric pump anyway!