Henry VIII's position of influence (6)
I believe the answer is:
height
'position of influence' is the definition.
'height' can be an answer for 'influence' (thesaurus). I'm not certain of the 'position of' bit.
'henry viii's' is the wordplay.
'henry' becomes 'H' (symbol for the unit of electrical inductance).
'viii' becomes 'eight' (synonyms).
'h'+'eight'='HEIGHT'
Can you help me to learn more?
(Other definitions for height that I've seen before include "size up?" , "Vertical extent" , "Altitude or elevation" , "Measure it from top to bottom" , "summit" .)