Deni - Not sure if the Herald set up is the 100% the same as the Spitfire (although they are obviously very similar).
But there was a hole in my lowering block that needed to be enlarged slightly for the rear spring to locate properly.
More details in this post:
http://www.madabout-kitcars.com/foru...&postcount=530
Finally, although I did fit a lowering block initially, I eventually removed it as the rear of the car was too low.
Hope that helps and good luck, Paul.