Following the lead above and inspired by DaveW's book I took the plunge. I made and fitted this cover made from 1.2mm sheet aluminium and some stainless steel stud/spacers. It seems to work although have few tools and no vice so it's not as pretty as some others on this forum. I post simply to say, if I can .... you can. it also seems to me that the lack of cover over such a vulnerable and essential area is something of an Achilles heel that should have been fixed at the outset - at minimum a Morgan upgrade part should be available ex factory.
Offside cover is fixed with 3x40mm studs into the empty cam cover threads - studs from a German supplier on eBay 40mm M6 male one end and M6 female the other - they work for both sides of the cover, both near and offsides
Nearside, secured by the same 40mm studs screwed down onto an available cam cover stud - I assume made available there for the Ford cover
The offside is secured with M6 hex bolts into the female thread of the 40mm studs - three in this case although 4 threads are available - space left for a suitable Morgan logo at some stage
At the front, it turns down shielding water ingress to the gulley that is home to the spark plugs
I re-routed the cable that disappears under the cover to go over the top, it has a tube shield over part of it but I'll keep an eye on this as it rubs on the heater pipe. I notice that others have fitted trim strip to the edges and I may consider this once I can locate it online.
Six months ago this kind of thing would have been unthinkable for me, this forum and your great advice has given me the confidence to approach this sort of work.