There are many places for anodizing but they have their own minimum $$$ order which isn't good for small quantity order.
Not every shop does type III and all type of plating and better to chose the shop according to your needs.
Some of them don't do preparation such as polishing, sand blasting or masking. So better to ask before sending parts.
I would choose local shop.
Have been considering getting a few parts from a flashlight done-- down the road a bit. Like looking ahead and not waiting till I actually want to get it done. Use to get some auto parts chromed and have had a few bad experiences with that.