Heavenly candidate, ultimately that woman in “non-party” colour (8)
I believe the answer is:
ethereal
'heavenly candidate ultimately that' is the definition.
'ethereal' can be an answer for 'heavenly' (I've seen this before). I'm unsure of the rest of the definition.
'woman in non-party colour' is the wordplay.
'woman' becomes 'Rea'.
'in' means one lot of letters goes inside another.
'non party colour' becomes 'ethel' (I can't explain this - if you can you should give a lot more credence to this answer).
'rea' put within 'ethel' is 'ETHEREAL'.
Can you help me to learn more?
(Other definitions for ethereal that I've seen before include "'Fairy-like, delicate (8)'" , "Light, delicate, insubstantial" , "Delicate - airy" , "Very delicate - tale here (anag)" , "Refined, airy" .)