Thank you all for your help and for your varied replies.
It seems to me that his name was Frederick William because this name has been passed down the each generations up to my brother.
I have seen the birth entry, which is a very poor copy, when viewing the original, just cannot make out the second name.
Don't know which way to go now but it's probable that all the Smiths in our family since him are not Smiths after all, but I suppose no one is 100% of their pedigree.