It all depends on where you live.
What kind of pellet guns? Airsoft or airgun? Either way, you don't need to have a license. For an airgun, i think you just need to register from the store you bought from.
It all depends on the county, state or country where you live.
See the link below for UK airgun laws.
no you cant, unless you have a license.
I do not know where Derbyshire is but from the name I guess it is in the UK. See the link Below for UK Airgun laws
Only if the airgun has a scope rail designed into the gun. You will also need an airgun scope not a firearms scope.
Yes.
You must have a license to own a BB or Airgun in Australia and be 18. If you belong to a licensed shooting club and pass a test you can be 12 or older
The highest velocity of an airgun is that of Evanix AR6 pistol which is 1000 fps.
Yes, you need a business license to open any sort of business.
Unfortunately the serial number doesn't help to identify the model. I need the model number to determine the age of the airgun. BSA ( as far as I know) only made 2 airgun models but made several different rifles that were under-lever models.