Chap joins new church for this reason (5)
I believe the answer is:
Here is my best explanation:
'for this reason' is the definition.
(I've seen this before)
'chap joins new church' is the subsidiary indication.
'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 "For this reason; in the future", "From this place or time", "It follows from that fact", "From now; thus", "Consequently", "In the future; begone!", "As a consequence", "Thus", "Therefore, consequently" and "From this time, or for this reason".)