Hi Ezza and welcome to the forum.

I'm afraid I'm not aware of any products they made unrelated to radiators.
Do you know which factory your father worked at as prior to 1967 they had one in Spon End which was replaced by council flats as well as the one in Canley?
If it was Canley then he may previously been employed at the neighboring Standard works which made aircraft back then.
I knew a lot of CovRad employees as they used to drink in Craven Street when I lived there, Eddie Hunter in particular. He once used the plating baths at CovRad to re-chrome our kitchen taps for us!
Some pictures of the Canley works can be found here:
https://www.28dayslater.co.uk/threads/c ... 21.130018/