We use the local abattoir (20 mins down the road) for the sheep and any male/castrated goats. We then keep them in their coldstore for up to a week (usually works out at 5 days and is free), then bring the carcass home (another advantage of Shetlands not being too large) in the back of the Skoda estate, and cut up on the dining table. We do not sell any of our mutton/goat meat. We normally leave the legs on the bone, take chops (sometimes), and cut shoulders and anything else up into cubes/chunks (for stews, curries) and mince any leftovers (shep's pie - my children's favourite dinner). I also always (because I can an dits mine!), go back for the pluck on the day of slaughter, the liver and heart get eaten by us the lungs and kidneys by the dog.
If you want to sell meat it would have to be taken from abattoir in refrigerated van to a licensed butcher, who then cuts up and in theory your customers would have to collect from him directly (so as to make sure it stays refrigerated until the point your customers pick it up. When we used to do that we always collected form butcher, then took straight to customer in cool bags. But we have decided that it is too difficult and expensive to do it that way, now I sell the occasional live lamb, deliver to abattoir and customer arranges with his/her own butcher to transport/cut up etc. I would charge for the live lamb and transport to abattoir.
I think that I would like to do it all at home, however the abattoir charges 17.50 per sheep/goat, and that seems to me good value in terms of my time/mess/need for gun/what to do with head/spinal cord etc. But it only works as long as we have abttoir at Galashiels. Problem is they don't like to "sell" you back your skins.