there are no street numbers for Swanpool St on 1871 census - very often houses weren't given numbers -there is no indication that it is a shop or that there are shops on the Street.
1872/3 a directory lists Levi van Bosch and Carl Lobeck as ship's chandlers at 40 Arwenack St and in 1871 Levi van Bosch 43 Ship Chandler ,wife Helena and son Meyer were at this address - no indication of this being a shop but looking at the property present day it looks much more likely to have been a shop in earlier year (my opinion)
1872 Carl Lobeck at his naturalisation gives his address as Falmouth Cornwall -no street given - he also signs his name as Karl Ernst August Lobeck
By 1881 Carl and family are at 40 Arawenack St
so was Karl in partnership with Levi van Bosch in 1871 and he moved into 40 Arwenack St after Levi left the area.
I haven't found Levi in 1881 but there is his death and probate record in Nov 1885 in Middlesex
May be worth checking out??
Suz