It’s ok,
No mayo is a good thing. It means it's unlikely there water getting in the oil, which means that it’s all sealed up nicely.
No puddles means, no leaky pipes, radiators or connectors. Which is good too.
So apart from an airlock in the rad, which you can sort out by running the engine with the radiator cap off, get it good and hot with the fan kicking in and fill up the rad to the top. keep it running for a good 15 minutes, if there is an air lock the water level will just drop, so you fill it up with water again. keep doing it until it doesn't happen.
To check the thermostat. Firstly let the engine cool down and then locate it.
In the Fiesta Zetec engines I think you'll find it usually on the righthand side of the engine. (looking from the front). It’s in a housing, on the engine end of a big hose that goes to the top of the radiator.
If you can find that we're laughing
I can’t get a specific photo but the housing will look similar to this
A thermostat looks like this
So if you found it and can get it off. Take it inside give it a bit of a clean and
the drop it in a pan of boiling water. If it does nothing its fooked. If the valve at the top opens up about an inch it’s ok so you can put it back.
They really are cheap about a tenner.
hope that helps