Creda Europa double oven fan problem… HELP PLEASE…

I have a Creda Europa double oven that has me a bit puzzled.
I’m doing this as a favor as the lady looks after my daughter for me while i work so the only money to be paid is for the part.
The oven is maybe 25 years old? It is the old brown one with the side trims that need to be removed to reveal the fixing screws. It has the large metal fan in the oven with the curly fan element.
This job has become a nightmare. Had problems with the fan catching and the motor sloping down as the rubber mountings have drooped a bit, however, I have overcome these problems. Thinking I had it perfect, re-installed it all and ran it. Worked fine until it got to 200o then it cut out. after a couple of mins, it cut back in and then it cut out again. removed the oven to look at my handy work. I noticed the fan motor was VERY hot so maybe the toc in the winding is opening up?
There is a small metal fan that fits in a dome behind the main fan blade, i wandered if perhaps i had fitted it the wrong way so i reversed it to find the same problem. One thing i did notice was the numbering for the tags on the new motor differed in their position from the numbering on the old motor but the layout of the tags is almost the same.
What have I done wrong?
I’m thinking the fan may be running in reverse and drawing the hot air over the motor perhaps?
any ideas?
Thanks in advance.
Robert.