Toppie, I went past Multiquip, they do not stock SS fastening buckles and dont know of anyone who stocks them. What they did suggest as the next best alternative a 25mm fully SS ratchet strap @R94 ex, but 60 might be a bit heavy on the pocket.
I was also thinking I use the bog standard (Midas) alloy fasteners on my duck and have done for nearly 2 years, and they are yet to let me down, as long as I keep them slightly lubed with Q8 silicone spray, in fact I think the straps might perish or fray before the fastener stops working, but all it depends on the application I suppose?