Azizi, you are correct - an Oss is a horse but said with a Cornish accent. And the Wee just means little. Obby is Hobby.
Saying Oss Oss to someone is a form of greeting - it can mean 'Hello' or 'Goodbye', 'How are you', 'Good luck', 'Cheers' or even 'Have a nice Mayday'! It's a very versatile phrase but it's also an 'in-crowd' password - only those people that know about Padstow will use it. In NZ we have personalized number plates available for cars and my little blue van has WEE OSS. I'm still waiting for someone to come up to me on the street and say Oss Oss! It hasn't happened yet and I've had that plate almost 10 years.
Alexander, I was talking about your Barry and I have a copy of his book. Years ago we discovered he had Henwoods in his family tree and my Henwoods were the ones who came to NZ 150 years back. We haven't actually found a link, apart from the name, but I like to think he's one of my kinsmen. I stayed in Padstow in 1972 and again in 1990 (it's a long way from NZ) and the locals always accepted me as one of their own.
I somehow lost my cookie temporarily because I'm not usually a guest - I have a page here and some photos you can visit if you're interested and I've contributed to some of the Padstow threads above over the years.
Oss Oss,
Robyn