Hi guys, first post here wanting to say hello to everyone and seeking a little advice/info at the same time.

Briefly, I'm a member of my local firearms club and shoot both a .22 rimfire BRNO rifle and a .357 magnum Winchester 94 AE underlever. I also shoot occasional clays with my O&U. I used to shoot rimfire and centrefire handguns until they were banned and owned everything from .22 to a Dirty Harry 44 magnum. I loved shooting them together with the re-loading aspect but alas events meant that the guns were banned. I've owned the mentioned firearms since around 1995.

Back in the 1970s I bought a fairly old and somewhat beat up BSA Airsporter which I now believe to be a MK2. It gave me many hours of pleasure during the late 70s for a relative pittance back then and last weekend, after around 40 years of it languishing in the loft untouched, I took it for an outing to the range to give it an airing, bearing in mind that it hadn't been fired over the intervening years. Externally it's quite pitted much as it was when I first bought it but mechanically everything works just as it did and I considered restoring it to it's former aesthetic glory or as near as I could but then it might be better to just remove some of the pitting but retain much of the patina it has gained over the years. That I can decide on later.

There are several regular club shooters who own among other things, some pretty tasty and I suspect very expensive firearms-rated air guns and they tested my Airsporter chronographically and even without replacing the spring which I did replace maybe 40 years ago and no servicing during the intervening time, the old Airsporter's output still bordered on the legal limit power output and we found it to be perfectly and repeatedly accurate at roughly 60 yards/55m with some old Milbro 13.8 grain pellets which is no mean feat for a gun that must be getting on for 60 years old.

So now to the needed advice. I've done some research on Airsporters and I think the one I own is a mid-late MK2 but I'm definitely open to being corrected on that by those who know better. So far I've not found any external numbering to confirm or date it etc. It has some of the classic MK 2 tell-tales like the flip down rear sight or the way the barrel is mounted to the rest of the body but what I'm finding confusing is the scope grooves which are from my measurements, 11mm apart. Most of the images I've seen of the MK2s have two separate sets of pronounced/raised scope mounting points but on mine it's a pair of grooves approximately 100mm long which to be fair look very shallow?

I know back in the early 60s I once owned a really early MK1 Airsporter which had no scope groves or points for attaching a scope and the only rear sight was a Parker Hale circular target sight mounted on the rear curvature of the trigger housing but that would have been a 1950s MK1 model.

Until recent years I have always enjoyed shooting with iron sights but sadly my main (right) eye has gradually deteriorated over time due to an eye injury acquired in 1988 which left slight blurring due to scarring from the injury so I needed to add a pair of scope mounts to my .357 Winchester underlever which was easier said than done, though a few weeks ago I was very fortunate to find a new pair of Weaver all-in-one scope mounts in this country for the princely sum of £20.00 and they have allowed me to add a decent scope which gave my centrefire shooting a new lease of life. I have a scope on my BRNO and I'll need to do the same with the Airsporter so I need to make sure that I get the correct scope mounts for my model.

Also the Airsporter actually kicks more than my .22 rimfire, in fact it kicks/vibrates as much or even more as when I fire regular .38 special loads through my Winchester underlever so any new scope will definitely need a scope that can cope with the vibration from the Airsporter.

I tried mounting the scope from my BRNO on the Airsporter but the mounts wouldn't grip the grooves due to the curvature of the cylinder and shallow grooves so I wondered how other Airsporter owners of this vintage got around the problem?

Many years ago I owned a cheap 2x scope which mounted firmly on this very air gun but at that time I preferred shooting with iron sights and 2x was little better than open sights so it was discarded. Now I wish I'd held onto it. The mount was hardly substantial (rather cheap and nasty would be an apt description) but it kept the scope firmly held.
Even if I can find one of those old scopes complete it would be better than nothing but I'd prefer to find mounts more substantial which will allow me to attach a decent scope which I can correct for my eye problem.

So any help or information would be greatly appreciated.

I've added an image of the scope grooves.

https://i.postimg.cc/xd2S7bLV/gunscopemount1.jpg