Newel post replacement

[At88]

Hi

I am looking to replace the newel post in my upstairs landing as currently too small and below the required height. My issue is with the size of the current post at 110x70...I can’t seem to find a similar rectangular newel and installing a square one of 70x70 would leave the outer part jutted out (if I were to cut off the old one at floor level)

any advice would be appreciated, pics below

 

[big-all]

weird one really
if you remove the cap is the top off the post showing added on timer on any faces ??