It's probably more important to identify where the oil is coming from than how much oil is leaking. 50ml doesn't sound like much (for those of us from the US how many ounces or teaspoons is that?).
you may want to locate the piece that appears to be the oil leak source then look it up in the manual. Put a pan underneath the leaking component then you can let us know both where the leak is coming from and how much it leaks in a set period of time. I feel certain there are Ford experts who can help you determine what's "normal" here.
Coolant disappearing after an overheat would worry me. I would first check the dipstick on the oil to see if there are any signs of milky sludge or something that might look like coolant contamination of the oil. If nothing, I'd check the oil level and the coolant level very systematically. For example, check them both cold, mark them, then run a set number of hours. Let them completely cool again (like for a day or more so they're as cold as when you first checked them). I would probably do this 2 or 3 times unless there was a big and obvious change that removed any doubt.
If over that 2 or 3 runs the coolant goes down, the important question is does the oil level go up? If so, you may have coolant going into your oil. That is bad, and I think you'd want a mechanic to diagnose and repair that.
If the coolant goes down but the oil level doesn't increase and you continue to see coolant leaking out under the engine then I suggest you ID the source of the leak. It may just be a gasket that needs to be replaced.
That's my thinking but I could be missing something. What do the engine gurus on here think?