1660bob, Im in the same boat as you, I found a late type front mudguard from Wes Scott Cycles here in Fort Lauderdale Florida, but no luck in rear, especially looking for the late type British market as its longer than the US version.
Ive been asking around and found a company in UK, they told me that the original press mold was scrapt, even asked SRM (they said if more people would request it theyd make it, PLEASE REQUEST
) and there has been no luck so far.
The only place I find them (have not the luxury of autojumbles here) is on ebay.co.uk but theyre expensive and found a nice one but sadly didnt have the money to make a bid.
Goodluck and if you find a place that sells a new late type steel guard let me know.