I put a new engine in last year and mistakenly assumed my shaft was 1". I bought an R&D coupling and attached it to the new engine. When I put the shaft in it was obvious that I had made a mistake - the shaft was 25mm and I had to buy a new coupling. ASAP would have taken it back if it was unmarked but tightening up the bolts slightly marked it. Thus - unused but very slight marks on a 1" coupling.
Going price is about £90 including p&p. What about £65? In central Edinburgh.
Just to clarify it's the 4" clamp on coupling: https://shop.tnorrismarine.co.uk/produc ... 4-flange-2