Looks as though the Britannia is anchored astern of and joined to the Hindostan which would have made it 1864 onwards, as in this picture. I was lucky to spend a short time on the last HMS Britannia.

[Linked Image]

Bruce
1964 4/4 Series V Comp (Megan)
1994 +8 (Maurice) tis no more
2013 M3W (Olga)