We drive ours to our tannery which is Devonia in Buckfastleigh. Our abattoir lets us collect our skins the day after slaughter, charges us £5 per each. The abattoir has salted them overnight, sufficiently for Devonia to accept them that day.
If we weren’t in driving range, we’d need to bring the skins home and salt them until they stopped oozing, then package them in waterproof packaging and courier them to the tannery of our choice.
I think one should officially need an exemption for handling “animal waste” in order to do this. I did a set of exemptions for the farm in Cumbria; it wasn’t arduous and didn’t cost anything.
Some folks here have in the past tried tanning themselves, using eco friendly products. The work in scraping and salting and stretching was deemed excessive and we are now happy to pay Devonia their £30 per skin for processing.