I was researching some of the older seed blends, particularly "South German" and "Sutton's Mix". Evidently, Sutton's Mix was used at the Valley Club of Montecito in addition to its well known usage on the greens at Royal Melbourne.
Replicating the original blend of Sutton's Mix may be difficult, but the answer to that secret may be found at the Museum of English Rural Life. They hold the records for Suttons Seeds Ltd. I unsuccessfully searched through their online database, but it seems like the only way to find out would be to go in-person.
https://merl.reading.ac.uk/collections/suttons-seeds-ltd/Supposedly it's comprised of various types of browntop bent (majority), velvet bent (small amount), and creeping bent (even smaller amount). If it contained fescue, it would've been to help during establishment and disappeared after a few seasons.
Over a century later, turfgrass breeding programs have greatly improved their products. It would be fascinating to see how the original blend would perform if the specific types of seed were named in the Suttons Seeds records. Obtaining seeds that were prominent 100 years ago is challenging, although a more realistic option is to utilize samples bred from the original mix.
The following U.S. Department of Agriculture application mentions two browntop bentgrasses that came from Royal Melbourne sampling in 1973. I believe they were "Egmont" and "Sefton", surviving descendants from the original Sutton's Mix blend.
apps.ams.usda.gov/cms/adobeimages/008900219.pdfThose two browntop bentgrasses are still commercially available.
When Royal Melbourne decided to get rid of its 1980's Penncross greens, they brought back something similar to their original greens. I've managed to track down PGG Wrightson Turf as the only grower of Royal Melbourne's modern iteration of Sutton's Mix. I'm sure they keep it licensed only to their club and Sandy Golf Links. It might be possible to create something similar using Egmont and Sefton, if the proportions for the other varieties could be located in the Museum of English Rural Life's records.