Yes, be careful about the use of MAM and unladen weight though. Unladen weight will be around 1650-1750 depending on model. I reckon (without looking it up) MAM of an Omega is significantly over 2 tonnes.
So, MAM of the trailer can be up to 1650-1750 - not a problem, but the combined MAM of trailer and Omega cannot exceed 3.5 tonnes. Given that the Omega's MAM will be over 2 tonnes I reckon this will put you outside the limits for a 1500 Kg trailer.
However:
1) Does the trailer have a plate listing the weights? If not who's to say what the MAM is?
2) This all seems to be complex enough that you'll get the benefit of the doubt at the roadside if not taking the mickey.
3) Failing that, all they can do is put you on a weighbridge and they'll probably find the combination under 3.5 tonnes provided the Omega is not loaded to the gunnels. Are they really going to argue that you "could" have loaded it up to a weight you're not licenced to drive, although you didn't? Again, you'll probably get the benefit of the doubt.
My Omega's max train weight is over 4 tonnes, and I've towed 1700Kg before so the car will be perfectly happy. It's just the licence that might be an issue.
Kevin