Coles Rail Crane

I recently acquired a builders plate for what I am told was a Rail Crane by Coles. Does anyone know of a way of checking the I D Number on the plate Thanks Les

 

An interesting site with much detail about Coles history.
https://sites.google.com/site/colescranedatabase/time-line
It can be seen that in 1939 HJ Coles sold out to Steel & Co. Sunderland.
All production at Sunderland was for the military and in 1946 all production moved there.

 

Thanks for the link. Interesting indeed, but unfortunately it doesn't help me identify the history of the plate.