TBH Paul, it could be both.
The springs determine the ride height, the shock limits the speed that it compresses.
Is the car bouncy? If you push down hard, it should come back up, then settle back just once at most.
More indicates worn shocks.
If the ride is too low, the propshaft will hit.
If the shocks are worn, they will allow the spring to compress more, propshaft will hit again.
What is the clearance to the road from the bodywork immediately in front of the rear wing?
Personally I dont know what an early model car should be, but the 2B should be around 7".
Try & find the exact model & other owners will probably supply their measurements.
http://nw.rhocar.org/identification.htm