I thought I'd have the same problem with an Orient Star Seeker GMT, a 42mm case with 21mm lug width. But it turns out lug width is never exactly what the manufacturer states because... manufacturing tolerances... : )
The Star Seeker happily accepted a 22mm Russian leather strap from Steinhart and it fit perfectly. So chances are you can go 22mm or 20mm with the V3 Bambino and you, more than likely, won't have problems. Also, straps can vary in their width.