Unusual nest boxes

You are right Benn, those metal ‘boxes’ must be so hot , especially if they are anywhere in the sun.  I am sure many a chick must have perished in them.  I wonder if it would be worth asking the manufacturers of them to make the holes too small for blue tits to enter.  After all cigarette buts don’t need that big a hole do they?  I wonder who we could get in touch with.  Goodness knows who manufactures them.  May have to investigate this! 
Sue