Scope creep was a real issue in those early days of mounting scope on air rifles.
The pressed steel integrated mounts that came with the low powered scopes really didn't help the matter when added to very shallow mount grooves machined into thin enough spring cylinder bodies. Its if they didn't want anyone scoping up their rifles.
They probably didn't as scopes showed up how poor most shot outside the farmyard ranges.
Its also interesting what scopes BSA and Webley bought in, or didn't. Though the adverts suggested there were badged scopes available, they could never be found in the shops.
When you did find one either they were really cheap, or very occasionally better than expected. But anything half good was never about long, and never on the shelves.
The Vulcan MKI was very prone to scope creep, any scope really needed bolting dow. Many a scope ring failed from excessive torque on the screws. True to most rifles then.
BSA's have vey little there to bind on, but at least an arrestor block was available that required an ugly screw to fix it on.
With the Webley Omega for once a decent rail was standard. It took FWB Aple mount with the cross pin. Rare Aple mounts and well worth finding. Sportmatch one piece can work as they have such long clamps. However, Sportmatch don't have the sharpest claws.
In all trying to find scope mounts that hold isn't easy. Period ones even less so. It wasn't that easy in the day either.
For the Vulcan then there is the Webley Telescan. The scout scope system was great, but typical Webley they let the product down by putting that very cheap pistol scope that were everywhere. The one for the Webley Hurricane and BSA Scorpion. If only they had done something a little bit better. But then the history of British old school air rifle manufacturers was pile it high and don't spoil the punters by giving something thats too good for them, something that they might want!