Easy bits,
A bottle with no test is £50 tops & that's if it looks immaculate, and you can find someone to buy it, pay for a test & you'll get your money back.

I'd also suspect that anyone looking for upgraded spec like that will already have charging kit so selling the rifle separate from the cylinder will probably get more interest.

Look on gun-trader & gun-star for an idea of prices at different spec level & condition.