I know we've had lots of posts about suplex, I drove PJB's car with the 5 link as well and said it was amazing……. but I don't think it was so much better to warrant the additional cost. (that's opened up a can of worms!!!!!)
Hugh, I don't know why you would think that would open a can of worms.
It is well known that I am a fan of Suplex and PJB's work but I certainly don't think it is the only solution. Peter Mulberry's work is quite correctly acknowledged as being excellent and he has been doing it for a fair while now. As far as I can see the main differences that the Suplex RS kit has are adjustability of ride height and spring pre-load, and the rate riser internal spring. It would also be a little softer on ride. What is going to suit one person's driving style and pocket may not necessarily suit another's.
It should also not be overlooked that the current production front suspension is much improved over previous years, even since my car that was built early 2012.
As for the 5 link suspension that is another story, particularly given the cost. It depends on one's perception of what a Morgan should be, and your individual analysis of cost/benefits. It was pretty much the same story with the Mulfab/Librands double wishbone front suspension. It was seen as a very valid solution but too expensive for many. That is certainly not a criticism of the cost: I am sure it represents the cost of fabrication and if they could do it for less they would.
It would not surprise me at all to see a 5L rear suspension available as an option on production trads within 12 months.