Is it worth, while they are newish and still okay, taking them off and spraying them with several coats of clear gloss lacquer?

Got round it, bought new wheels.

Don't! only warranty item for 6 months (see my thread above about external trim warranty...centre caps in my case too

My dealer replaced mine at 14 months due to corrosion no questions asked

Had all 4 of mine replaced today along with an alloy that had a bit of water ingress on the polished part. Car is 20 months / 24k. All done without an eyelid even being raised.

Is it worth, while they are newish and still okay, taking them off and spraying them with several coats of clear gloss lacquer?

I was thinking the same thing.  I'm not sure if the lacquer might react with either the existing PU coating, or the aluminium we are trying to protect.  Trying for a warranty replacement might be a better idea.

Apart from the wet I think the salt put on winter roads doesn't help either.

2 winters ago I bought a set of new Octavia alloys from a bloke in Austria off eBay.

They came with a set of hub covers too. I used one set for winter and my original ones for the summer months.

The summer ones are fine the winter ones look much worse for wear.

I was thinking the same thing.  I'm not sure if the lacquer might react with either the existing PU coating, or the aluminium we are trying to protect.  Trying for a warranty replacement might be a better idea.

I have since obtained another set and have done what was suggested, three or four good coats of automotive clear lacquer on them.

I have also done the same on the center caps on my aftermarket alloys which I currently have fitted, early days but all holding up well.