This watercolour of 'Greenwich Hospital' was made from almost exactly the same viewpoint as Chambers's oil painting of Greenwich hospital (1836) now in the National Maritime Museum collection in London. If both versions are topographically accurate, the absence of certain buildings in the Walker's version would indicate it was made before 1836.
B T Carter (former Assistant Keeper of Prints and Drawings at the National Maritime Museum) previously suggested attributing the Walker's watercolour to George Chambers Junior (1829–1878), Chambers' son. This has been rejected though as the gateway seen in the picture was moved in 1842, meaning the watercolour must have been made before this date, if not before 1836. George Chambers Junior would have only been 12 or 13 years old in 1842 too.