Good to see you have had the paint brush out John and look forward to anyone confirming the Z82 seat being of Harris origin.
I have been digging in my literature and found a picture of the No 3 Front Cut mower in the only Harris catalogue I have, you can see the gearbox cover quite clearly in one of the photo's. The cast iron seat is not the Z82 in these pictures, but a heavier duty seat with vertical slots can be seen.
Harris literature is certainly very scarce, this piece of mine was found in Yorkshire, England several years ago, it covers mowers, grain binders and sail reapers. I would be interested to see any other Harris literature anyone has in their collections.
Malcolm.