Early Christian vacancy in Wales discovered (7)
I believe the answer is:
apostle
'early christian' is the definition.
(I've seen this in another clue)
'vacancy in wales discovered' is the wordplay.
'vacancy' becomes 'post' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' is an insertion indicator.
'discovered' says to take the centre (dis-covered - outer letters removed).
The middle of 'wales' is 'ale'.
'post' going inside 'ale' is 'APOSTLE'.
Can you help me to learn more?
(Other definitions for apostle that I've seen before include "Disciple of Jesus Christ" , "Principal champion" , "Ardent espouser of new system" , "To lapse (anag) - ardent supporter of a cause" , "Thaddeus, perhaps" .)