Animal health, the application form is called an abp1117 I think, but if you google approval to transport animal by products you'll find it. Once applied for, it gets sent to animal health, galashiels, they send out an approval for the premises then book a visit. She just wanted to see that I was planning to keep the skins somewhere secure away from livestock, and advised me what I will need to keep records of - when things go to abattoir, in movement docs already; when skins come back, where you get a document from the abattoir; then any records of sending away to be tanned, once tanned they don't care any more!