In the scene following Constantine getting kicked out of the bar, his hair is a lot blonder than before.
The van driven to the club by Ray is 60's era left-hand drive Ford Econoline - the Econoline is and was not available in England, except as a (very) rare import . The British Ford equivalent is the Transit, made from 1965 - present.
The van Ray is driving has the registration GHJ 221Y. The "Y" registration (not manufacture) period ran from August 1 1982 to July 31 1983 - a vehicle registered in 1977 would have the letter "P" if registered before August 1 or "R" if registered after. The van depicted was manufactured between 1961 and 1967 and could conceivably have just been imported and UK registration granted, which means the correct registration should be GHJ 221R with black characters on a white background.