This quite tatty cover has a hand stamp, upside down, middle top, which I have not seen before. It also shows the red "General Post Office Hobart Town" large circle hand stamp with a "Paid London" smaller stamp applied over the top of the larger marking. It appears to have been re-directed in the UK and I wonder if the unknown hand stamp is a UK marking perhaps related to the re-direction? It appears to read "S???? mark Branch" with "S.E." below - see enlarged scan, inverted for better readability, below.
Any comments very welcome.