Antique English Spoon Found in Sweden

Photo shows spoon with touch or maker’s mark inset
I recently received this letter:
My name is Anders from Stockholm, Sweden. I am writing to you with hope that that you might be able to bring some further clarity over a find my great grandmother made some 70 years ago. While digging in her garden she suddenly found an antique spoon made of latten, which has been kept in the family ever since, this was in the 1950s. The find was made in the village Hov close to the town Vadstena by Lake Vättern I Sweden. This area was an important center of power in Sweden some centuries ago.
From reading your book, The Essential Guide to Old, Antique and Ancient Metal Spoons, I have come to the conclusion that it is a latten spoon from the later part of 17th century, with a strawberry knop and a maker's mark of three spoons, one inverted, surrounded by a dotted circle. Visible in the mark is also one initial, an "R". The second initial is no longer visible. There is also a line along the "handle".
From your book I understand that the spoon might be British made, both the spoon itself and the maker's mark looks very similar to some of the specimens in your book. Is there anything else that you can tell us about our spoon? For example more precisely when it was made, where and by who. And what kind of person could own a spoon like this back in those days? And do you know anything about spoons or other British object of this sort to have been found in Sweden or the rest of Scandinavia. Just any piece of information would be of great value to me and my family.

Dear Anders,

Many thanks for your email and pictures. Your spoon is a really lovely find. Unfortunately I am not going to be able to add much to what you have already deduced from my book. While I have found more information on silver spoons, I have yet to find anything else on base metal spoons up until the receipt of your email.
On the balance of probability I agree with your identification. The spoon was most likely made in London, England. Continental spoons rarely have a touch mark or maker's mark. I am a little concerned with the apparent roundness of the bowl, which suggests it may be earlier than 17th century but the maker's mark ties in very well with the RS triple spoon motif with decorated bowls, active in the 17th century. If you look closely you can just see the letter S. Unfortunately the register of makers' marks was destroyed and it is now almost impossible to determine who the maker actually was.
Base metal spoons before the eighteenth century would have been used by the middle classes of society - merchants, yeomen, etc. The upper classes would have used silver (and gold) and the poorer classes, wood or bone.
If anyone can add anything further to this find, Anders and I would love to hear from you.