I really like the idea!
Even if there's several people doing similar thing it would help. E.g. two people keep sheep in the orchard. One of them makes sheep from both holdings into burgers and sausages the other ones makes apple juice or apple pies from both orchards. They sell it together as you suggested.
If you start you start something like that I would be interested in joining but from east midlands
Exactly this. There must be hundreds of smallholdings just in the southwest that all have a handful of fruit trees (for example) that aren't worth anything individually. However if they teamed up a cider maker could collect all the fruit, turn it into cider, sell it and everyone makes a little money out of a previously wasted resource.
Same goes for so many things, everyone says it is really hard to make money off a handful of sheep or a handful of cows etc but if they teamed up costs would be lower and profits equitable or possibly even higher.
One of my pet projects is trying to get brewers co-operating more, 3/4 of small scale brewers struggle to turn a profit yet they all rent their own buildings, own their own equipment which only gets used 1-3 times a week, run their own vans half empty etc. None of them seem particularly aware of the huuuuge cost savings and potential extra sales if they shared a building and equipment etc.