Long time reader of these boards but first time poster
I was just in Montevideo a few days ago and needed some work done to my bike, I'd seen this thread and went to Willi Motos.
Turns out Willi is the Uruguayan importer for Royal Enfield Motorcycles. I didn't meet Kevin, but I did meet Jose and Aldo who own the mechanic's workshop side of the business. All three are great people who were very helpful and professional.
As mentioned before, Willi doesn't speak much English, but he has traveled around South America by motorbike extensively and can provide some useful information. Jose and Aldo both speak good English. I highly recommend these guys!
I think the address is actually Solano Lopez 1686, but it's hard to miss, and it's right next to a supermarket.