I've been doing a bit more digging on William Carter and have been able to find a few more details.
In 1881 he has left Writtle, Chelmsford and has moved to Bowling Alley, Harpenden, Herts. where he is the landlord of the Woodman's Arms. He is there together with his wife Charlotte (nee Curtis) and his children George, Ellen and Henrietta. Interesting on the same street we find his daughter (Hannah Cecilia) Charlotte living a few doors down with her husband Joshua and children Alice and George.
I have now found baptismal records for Hannah Charlotte Cecilia and Jessie Maria Charlotte. They were both baptised at St. John's, Wapping on January 7th 1859 and their parents William and Charlotte are living at 4 Little Hermitae Street. In the 1861 census they are all in Writtle, Essex.
I also managed to find a record of the birth of their daughter Ellen Charlotte Curtis Carter on 30th January 1865. By this point the family are back in London and living at 22 Medcalf Rd, Enfield and William is described as a 'fund holder'. By 1871 William and Charlotte, together with their children William, Charles and Ellen are in Harpenden. Their daughter (Hannah Cecilia) Charlotte Carter appears as a domestic servant at Hatching Green, Harpenden.
So, a few more facts. The family seems to have moved a lot. Yet with William living on the same street as Charlotte's future husband and his family one can see how they met. Still nothing on Charlotte past 1881 I'm afraid. I'll need to get that marriage certificate .... Hannah C Charlotte's son Harry was in the Welsh Regiment, his record hasn't survived except a medal card but perhaps I could try the regimental museum.
Matthew