In addition to checking
www.willtheyfit.com, it’s also useful to check some of the online alloy wheel retailer websites. If you input details of your car and filter the results of suitable wheels by diameter and width, you’ll be able to see if any have an offset of ET48.
I’ve just done this for a 2017 Leon FR facelift on the Rimstyle website and the search results do include alloys that are 8.5J x18” ET48 - see screen shot below;
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