Yep, they were top drawer. Evans neither made them nor finished them. These are standard Webley W & R 1st Models (54 pounds in 1914), and were supplied complete to Evans. It's long been known that William Evans was a retailer before the war, and that their pre-war double guns were amost entirely Webley products, and bear Webley serial numbers on the barrels in addition to Evan's own numbers.
I haven't talked to anyone in the trade that believes that Evans was finishing any of these. I had a nice talk with a guy at SCI that worked for Evans for many years and spent quite a bit of time rooting around in the records. He said that there was no question that these were being bought in from Webley complete.
I believe the fence carving is known as "trefoil motif".
