I know this is an old thread, but seemed a good idea to say about my experiences of leaf spring 'lowering' in case anyone new was thinking of lowering the rear without flipping the axle.
I lowered the front of the van using 35mm Mk2 Focus lowering springs last week in readiness, then took the van to a leaf spring specialist Saturday just gone (
www.leafsprings.co.uk)
The result was an extremely professional service and a perfect drop / ride height for me (conservative drop of roughly 2 1/2") as i use the van occasionally for mobile DJ'ing and PA hire. Not full load cap, but still loading 300+ KG's in the back, so didn't want it to be decked.
Ride is perfect, not too firm, but enough that it has vastly improved the handling (coupled with new tyres all round) and being a high top, it is far less top-heavy round sharp corners, and has lost virtually all excess body roll!
I DID however run into a slight problem though.... It was discovered once the springs were removed, that one of them had a fracture in the metal, and was advised that it would not be a good idea to re-shape the spring in case it broke once cooled. But the guys at the workshop had a new one ON THE SHELF, and charged me £75 for a complete new double leaf spring, which i thought was quite reasonable. The other original leaf had already been changed at some earlier point, so was still good. All rubbers and bushes replaced as standard.
Before refitting, the springs were treated to a re-spray and now look new.
K