I've had a proper look at the GRO site now and bought the digital copy for Florence. Her birth was registered 6 weeks later by the mother who is recorded with a slightly different maiden name, and the father as her husband, even though he was remarried and having children in the US! I'm glad I'm not a direct descendent, I will just have to leave it....and assume that he was going back and forth and was highly fertile! 😃
Thank you again for your help.