Well it should be possible to tell you - it might just be me being thick, but the lozenge doesn't seem to agree with the first period details - which it should - if the date is 1843.
Where the figure 15 is, there should be an upper case H, which is the year letter for 1843. Numbers in the top segment indicate a date post 1867 - and then the H is in the correct place for 1869 - trouble is then that there should be a letter in the bottom segment, not a number.