If you're based in the UK, not a huge amount of need for oiling, although I'd maybe just give it some oil on the exposed bits of wood. Just helps to protect from rain and from drying out too. (More the former for me as it rains a lot here)
In terms of knocking, they don't generally need much, but bats are getting expensive, and you do give it the best chance of surviving by hardening that top surface, so I'd give it a good amount around the toe and edges, a just a little up and down the middle to the stickers. Going by how expensive bats are these days, it's even more incentive to give them the best chance of surviving a few seasons!