I'm not really interested in racing the engine in the UK as this is more of a practice engine for my 3 year old boy. Furthermore, I'm not located in the UK but in the South of France. We are planning at some point in the next years to come to the UK and race with kids his age but this is really just a training tool. I've tried to find a comer website or company information but I couldn't find anything. Would you know where I could check the serial number? On top of that I couldn't find anything on the web.Your best bet for checking whether it was a C52 would be through Comer themselves. From what I understand any new motors are C52. They've also been designated as C50G in this country (G standing for Green).
The issue you might have with your motor is that if you want to race it in the UK, it has to be tagged. As you've bought it from abroad, I believe you won't be able to use it in MSUK governed events because Zip Kart do the tagging and log booking over here. You might be able to run it in IKR events though. You might want to touch base with Zip Kart to see if they can do it, although if you could, then I'd imagine everybody would be doing it.....
Thanks,