Ah, the 113 shape is one of my favorites. I have never known who the designer was, it's not one of the shapes that you see associated with the famous names on such charts. I have a newer one in the golden danish finish...used if for Reiner LGF for a while but have switched it over to Fillmore. Here's a pic of mine on the right:
Light, good balance, medium bowl capacity. Elegant long oval shank with a brandy/billiard hybrid shaped bowl. The bowl seems to me to be at almost exactly 90 degrees (although I haven't measured), as in the slight forward lean or cant that would be common to see on most straight pipes of this nature seems to be absent. It's a very straight "proud and upright" sort of posture for the bowl, even though the bowl isn't all that tall.
Keep in mind that alot of Stanwell shapes have gone through slight evolutionary changes over the years, so one that is 30 years old may not be exactly the same shape as a new one, but they will share the same basic idea usually. The stanwell shape 30 (a sixten design I think) is a good example of this.
I think I found your ebay auction with a search of completed listings. I would say you may have paid a slightly higher price than I would have (assuming I found the right one), but I don't think you got hosed or anything. I wouldn't fret over the price since I suspect you will get a heck of a good smoker, and it's likely only going to increase in value as time goes on (if you take care of it) since Stanwell is out of business now (or at least has changed hands and nationalities).
Some estate stanwells are going for higher prices on ebay these days than the same pipe would cost new, and some new ones are going for higher on ebay than you would pay from an online vendor. The one you got looks to be in good condition from the pics on the listing.
Assuming the pipe is actually 30 years old or so, I think that is right around the time they stopped using the reg numbers but I can't recall exactly. The pipe looks to be in good shape for that vintage.
The reg # pipes are going for a fair sum these days on ebay, but your ebay listing didn't say anything about a reg #. That seller would likely have mentioned it if it was a reg # pipe.
Also see this thread for a list copy/pasted by PB as well as a link to an english translation of a forum w/ additional info: https://www.brothersofbriar.com/t8421-basil-stevens-stanwell-shape-list