OK, I tried to identify this in so far as I can.
I’ve expanded the image, cleaned up the background and marked up some of the key points. It's quite a big image now, so I've used a different upload site:
https://easyzoom.com/imageaccess/beef21a9632e4834ba13306c696e026c
After doing all that, I tried to identify this in so far as I can.
I’ve expanded the image, cleaned up the background and marked up some of the key points.
First of all, it looks like there should be a semi-cylindrical cover that protects stray fingers from the powerful mechanism.
It’s also worth noticing that the spigot at A is first fixed to the main body and second, appears the spigot to be hexagonal. The hex shape suggests that someone should adjust it with a spanner, or that it fits snugly into a recess on another object. Not sure about that.
Second, the two mechanisms at B and C look like they are canted over to push the bolt (?) forward. It looks as though these hinges can move the plate toward the spigot (A), against the spring. That would prime the mechanisms, allowing some kind of trigger to push the bolt forward.
I suspect that the means for doing that is on the reverse side. The shape at E appears to be a kind of access point with protective plate.
Then there are the adjustment screws (D) – one is missing. Can’t really see the purpose of those.
Finally, there is the tall, out-of-focus thing.
This is a red herring, but the transition between the straight, vertical bit and the curly bit looks like an old soldering iron. I think that is probably a bad guess. However, it could be some kind of heating element.
Windings like this are sometimes used to carry threads or fibres, so that the thread is easy to load, but moves easily. However, I cannot see any polishing that you would expect from such a thread.
My initial thought was that it is a mechanism from a gin trap, or equivalent. The animal triggers the spring mechanism, and the thing then snaps sut. The top piece would be a guide to support the traps. It’s bent like that to adapt to different situations.
However, looking at the area around mark E makes me think that there is a handle under there that controls the mechanism. It’s possible I edited the image badly, and the shape is just shadow on the Tesco bag. Even so, there is a big lug under there that appears to be some kind of actuator.
Can’t help much beyond that. Date-wise it could be anywhere from late 1800s (machine-made spring; fine machined threads on the adjustment screws) up to 1930s when cross-head screws came in. These single-slot screws are difficult to tighten effectively.
You can’t see the screw heads at D, but if they are also slotted heads, then I’d say it is for domestic use. If they are Allen screws, then maybe more industrial. However, the Allen head was only invented in around 1910, so not much of a clue there, either.