Yes very difficult to get hold of and from Ford it is impossible to get a clear answer...
I did consider ordering from Burton or Graham Goode, but being from Denmark, the price + shipping + customs charges makes it very expensive.
A friend of mine might have found a solution...
It seems to be identical to the one on a Volvo 210/544/140
Measuring 61,29mm across and 23,82 in diameter.
Price was about 20£
I will update this thread if it fits.
Fingers crossed