Chap joins new church for this reason (5)
I believe the answer is:
Here is my best explanation:
'for this reason' is the definition.
'chap joins new church' is the wordplay.
'chap' becomes 'he' (**).
'joins' says to put letters next to each other.
'new' becomes 'n'.
'church' becomes 'ce' (abbreviation for Church of England).
(Other definitions for hence that I've seen before include "As a result", "From now; thus", "It follows from that fact", "In the future; begone!", "For this reason; in the future", "This is why", "As a consequence", "From this place or time", "Thus" and "Therefore, consequently".)