Dating campari bottle

Got this one recently from my 90yo grandmother. My grandfather past 30ish years ago and was known to drink it now and then. Bottle doesn’t state an abv nor bottle volume. As it is slightly bigger than a wine bottle I assume it’s 100cl. Rear states L S/1305D but I don’t know how to translate this to a production date. I checked various auctions site but couldn’t find similar bottles. Could use some help!

Yes, I just opened it to have a drink on my ancestors. Now I’m curious, no plans to sell.