Unfortunately this is a sign of the times, we had my GTD and the Mrs's MK3 Beetle go in January off the drive. Within two days the Beetle (well its shell !) was dumped in Birmingham minus everything except the rear wings, exhaust and chassis. Yep that's right they had stripped everything including engine, gearbox etc.
We found the wheels on eBay within 3 days (was 70's edition model so only 30 registered in the entire UK with those wheels) and could see in the images little kerb marks I knew and was wearing the same make of non-brand cheap tyres we had put on her a few months before (mrs is tight on tyres !). Anyway sent all info to police, do you know what they did about it ? Yep, nothing, not a thing ! They just don't have the resource to do any investigative work for things like this anymore ! Sad state of affairs.
Anyway, sorry to hear your woe's. As already suggested get a marker system (smart water etc.) and mark up them parts ! Already done my new cars on most externally removable parts.
Bets of luck !