Here is the template.
I thought I had some A24 but couldn't find them. Anyhow, all the A series has the same mechanical structure. I checked it with A10,11, 12, 16, 20, 22, 25, 35, 39 etc. all the same. I also have the UTC catalogue but it does not give a template.
Mounting hole centres are 29.6, I made the screw holes 3mm which is slightly larger than the original. This is good because it gives you few tenths of a milimetre for aligning. Centre core for the solder tabs is 33mm in diameter, and I have also been generous on the aperture of the ground tab. It is r4 or 8mm in diameter and 20mm from the centre. I indicated it that way because your engineer will always reference to the centre.
Good luck.