Davie, from the information I have to hand, the 416GTS comes in at 1223kg MIRO, with a MTPLM of 1439kg.
The Mondeo. depending on exactly which model it is, ranges from 1283kg to 1500kg kerbweight.
If ou have the basic 1.8 @1283kg, then you are well over the recommended 1090kg , and over the cars kerbweight.
Even if you have the heaviest version, the 1.8i hatch, the kerbweight is 1500kg, with a recommended van weight of 1275, and a MAX towing limit of 1500kg.
Whichever way you look at it, you are either towing at a minimum of 95%, which is not good practice, or are over the kerbweight of the vehicle, so over 100%.
In short,,,you "think" its ok, but in reality is is far from so, and you would be putting yourself, your family and everyone elses lives at risk with this combination.