Hello Andy and welcome to the Collector's section of the BBS.
You have an early 1970s Premier. Not every E Series Premier was stamped with a code letter and your 5 pin model matches this series. I can't quite make out if the finish is blued or has been coated over with a lacquer type finish, which Webley used for a while during the early 70s. A date was usually stamped under the left stock side/grip and I can't quite make out if yours was ever date stamped. The stamp will be found about half way down the grip.
The Premier was a fine pistol and there are many variations to collect, as lots of changes were made to the design over its 13 or so year production run.
Hope this helps.
John