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..... there's always one, isn't there ?
Have been trying to find out myself as I have the same problem. There was a guy on here some time ago who had a friend who was setting up a local business to rechrome drums and although I enquired I heard no more from him. If you find anyone, please let me know and I will do the same.
Any small machine shop would be willing to re-knurl the drums for a price but your putting a high value object at risk if they cock it up. I had some Lewmar 40 winch drums straight knurled a few years ago. these were bronze so I did not bother to re-plate them & they're are still going fine. If your drums are aluminium as you seem to suggest re-anodising could possibly be done by you local plating company but if the drums have any steel inserts of fasteners fixed to them I think they would need to be removed first.
Mine were re-done by SilverBronze in Surrey. Not cheap and I had to ask them not to polish the bodies prior to plating, their surfaces weren't too bad but the chrome had started to flake.