I fitted mine without a sandwich plate. Got a tee piece to allow me to fit the oip pressure sender and standard oil pressure switch to the block where the oil pressure switch fitted.
Made an adaptor to fit into the end of the standard oil filter housing to fit the temp sender to. All I had to do was drill a 10mm hole in the power steering bracket to allow the cable to pass through. I was able to run the cable around the bracket so it did not foul on the belt.
Think I still have a spare adaptor. It has a one eigth BSP thread for the temp sender.
£10 posted to you, comes with crush washer to stop it leaking oil out the housing.