Hello both, sorry for late reply
Erato, thanks for the info regarding (both) Crystal City. The only other family name might be Bradley (the maiden name of Franklin's mother, Frances). As far as I can tell, as Milliepede mentions, Franklin was indeed a mechanical engineer, possibly working with steam engines, which may well have been of use in Crystal City Missouri. I believe they left the UK because he had been declared bankrupt in 1884 and may have been escaping his creditors, so that could of been a great place to lie low for a couple of years. Thank you both once again