Thanks for that, I hadn't seen that census info. I didn't actually track exactly when Isaiah Jnr and family came back into the UK but it had apparently been a few years if they were on the 1901 census. I know the family went back to St Helier in later years too. I'm not sure if you know but the Channel Islands, although part of the UK for records etc is quite separate in a lot of ways. A very small set of islands and quite a distance from mainland UK. In fact physically far closer to France with a big French influence too.
But I still can't see where Dorothy was by 1905 when her parents and brother left for Natal.