Hi Janet, Just started to look at this again after a while.
I have got Jonathan & William Lewis in the census' from 1871-1901 if you are interested.
It looks like they moved from Eaton Bray to Highbury in about 1872. The addresses in Highbury were in Hornsey Road, at the Ashburton Grove end. (Right were the mighty Arsenal F.C. are building their new stadium)
I hope to be going down to Islington in a couple of weeks and maybe find the houses/shops if they are still there.
Let me know if you want the census info still. Marc.