Hi Richard,
Am not certain about a MK1.5, have not heard of that term. ?
There is good information on the North American MK1A or B, I can't seem to see it right now.
I just googled and found a web site,
http://mk1mr2.webs.com/mk1amk1bdifferences.htm this is UK.
In NorthAmerica is a little different ,not all "B'" s have electirc antenna.( possibly other differences )
The biggest difference I know of is the side skirts, MK1B is with skirts.
Is the Mk1.5 to do with displacement ?
If you want some info on you car , I could confirm engine size and other basic info if you let me know the serial #
Or others can jump in, re MK1.5 ?