This is the 406 Mercedes Bonna 2500 Ambulance. I believe it is in 1/35 scale as it measures 5-3/4" long. I got it off Ebay for my ambulance collection. I have also found many more in different liveries. You can see them at the following pages.

Red Cross Issue

German Issue

Austrian Issue

Blue Cross Issue

St. Bartholomew's Issue

Norwegian Issue

London Issue