Hi,
Posting pictures is easier to do than explain. Basically all you need to do is register to one of the on-line photo hosting sites (eg Imgur ) which is free and allows a certain amount of resizing and editing. Then upload the picture from the folder on your computer and and copy the associated link directly into your post.
Many people soon become disenchanted with compact spring powered air pistols as they are not the easiest of pistols to master, but persevere and they can provide more satisfaction when you finally start getting results. I have been lucky enough to shoot many formal and informal target air pistols over the years and although it's easier to shoot with the more expensive target oriented pistols, the fun to be had from just plinking in the garden with a springer is often just as satisfying.
What calibre is you Premier ? Iv'e found .177 to better if you are looking to shoot reasonable groups on paper targets, but for shooting tin cans etc in the garden either calibre is fine. I can also recommend RWS Hobby pellets in either calibre as being accurate and reasonably cheap to purchase.
With practice, sub 2" groups are consistently reproducible using a one handed precision hold at ranges out to 10 metres, but errors in technique are punished far more severely than with pre-charged target air pistols, so the more you practice the better you get. Although it's nice to try and get reasonable accuracy from pistol shooting, you also need to keep it fun, so informal target shooting or just plinking in the garden have their place. I also find combining shooting and collecting these older air pistols more gratifying than buying and shooting some shiny new pistol without the character and inherent build quality of the older models.
Webley stopped using Ser Nos after the war and starting using batch Nos which are not helpful when trying to accurately establish a manufacturing date. The 631 stamped on you pistol is a Batch No and could possibly have been used more than once.
Regards
Brian