Peter, I had this on my +8, and have it on the Roadster. I noticed that when I fiited inner wing liners to the +8 the problem became less. I fitted the wing liners to protect the wings from stones flying up and causing dents/paint starring due to the poor roads especially where we live. The other benefit from the liners was everything kept much cleaner underneath. I think the spray issue diminished as the water from the rear tyres was more limited to how it escaped the rear end of the car. It did not totally eradicate it but helped.
The liners I made using black corian sheet 4mm, and marked the edge of the wing with masking tape and the measured to the inner side of the wing and then transferred to the sheet, joined the dots and cut out the liner. Initially cut oversize and then trim down before final fit. Ther rears are easy to fix, for each side cut 4 stainless flat bars to clamp around the rear wing stays, 2 clamps each side, drill a holes at the lower point of the bar to bolt through the liner and use penny washers, the front edge of the liner can be fixed using the front wing to rear wing bolts. The fronts are a bit trickier, you need simpler supports for the rear edge to wing stay and these need to be bent to the appropriate angles, to fix the top and front you need a long s/s bar, from top of the king pin area, which can be bolted to the upper wing stay, this is bent into the shape of the wing and stops below the headlight with a T piece on the end bolted or welded in place, the front of the liners is then secured using 2 bolts and penny washers to the T bar.
It will take about a 4-8 hours depending on competency and tools to hand for cutting and drilling stainless. None of the above requires any holes to be drilled on the Morgan. It's well worth the effort and relatively cheap.
I have to to mine for the Roadster, have all I need but have not had time yet, but hope to do other the next few weeks, when I will post pics etc. as I promised for others on ™.
