I'm trying to recall the name of a show made in the early 90's but set in the early 60's.

i'm pretty sure it was a cop show.

it was on UK screens late at night, around the time of Tour of Duty.

The opening title really focussed on the cars of the time with a cool period theme tune

i'm sure someone knows what it is, i just can't remember!

Wild guess, but perhaps "Crime Story?"

http://www.imdb.com/title/tt0090410/

Yes! That's it. Thanks!