Stewart - you haven't said in your RootsChat profile where you live, so I don't know if a trip to the Heritage Centre would be feasible for you. If it is, there is a permanent exhibition there about the work done in the Royal Arsenal, and although they may not be able to tell you anything about your ancestor, they may at least be able to give you a picture of what life was like there. If you're not able to make it to SE London, then I've found that the people at the Heritage Centre will give some information by email if you request it.