I was searching around for pictures of the Labatt's cars and had a nice little find:
http://www.btccaction.co.uk/results/1990/rd1.php
The results only seem to be accessible through the "Select Result" dropdown box (selecting 1990 doesn't work), but the site has results from every round! No qualifying times, but full fastest laps data. A quick shifty through the forum suggests that the results might have come from Autosport.