I would direct this question directly to BSA at the link below. They would have the best answer.
BSA made 8 different Meteor model rifles starting with the MK1 to 6, MK 6 Carbine and a Super. Identify your model and state the condition of the rifle to get an estimate of value.
you could be looking at a Meteor MK IV and think it's an "N" this model was produced from 1973-1977. Or you could ask BSA directly at the link below.
There are several versions of the BSA Meteor. So I will break it down. MKI, MKII, MKIII, MKIV, & MKV. In immaculate condition around $160-$180. MK6 $270-$320, MK6 Carbine $295-$350, Meteor Super $185-$210
it depends on the model. See the link below and select you model to see the diagram.
No. Not cost effective.
There are a number of places that an individual can find BSA rifle scopes. Some of the places you may want to try include BSA Optics and Air Rifle Scopes.
It was manufactured between 1946-1959. one in excellent shape will cost around $200
Because of the nature of the PCP power plant I suggest you search the net and look for air gun repair or air gun tune-up. There are shops that tune up air rifles and modify them.
BSA cadets were made between 1946-1959
The BSA Mercury was made between 1972-1980
I suggest you contact BSA Directly at the link below. They may be able to help you.