Perhaps this has been posted before, but while looking for a company that puts out original paint colors, I came across this web page. Just start by putting in your make (in this case its British Leyland) model year, click on the chip chart and look for the BLMC code for your paint. You can even buy the paint in aersol (rattle can) cans. Drag the cursor over the paint chip and its magnified. I'm not sure what brand of paint is being sold, but I was looking for PPG products when I came across this.
http://www.tcpglobal.com/autocolorlibrary/