Replacing this newel post with two in line ones

[Pheo]

Anyone got any thoughts on replacing this newel post? I'd like to replace it with one running parallel to the stringer, and then one running in line with the (to be fitted) basebail running along the top of the joist.

I can't work out how its attached, due to the many many years of abysmal glossing (why did they bother!!). Anyone had any experience?





Cheers!