Size of lights for light pod?

[midlandscarshows]

7 inch Paul. Although I'm led to believe that the works cars had a slightly larger light, taken for stock for the front of trains.... Also used as runway approach lights apparently. I'm still trying to find out where
No specific templates but if you use a lamp nest to carry the unit then that'll give you the correct template easily enough.

Guy

Thanks Guy , where would I get a lamp nest from please ?