It seems pretty reasonable to think that in 1836 John was the Junior Town Clerk but by 1848 (the date of the attack) or later (the time of the trial) was the actual Town Clerk ...
Junior Town Clerk was most certainly an occupation as a Google for (with the quotes):
"junior town clerk"
will find.
And even
"deputy junior town clerk" gets a hit !!
Perhaps the attacker John THOMSON was transported to WA which had later transportations - or was pardoned before being transported: I have a person convicted to transportation in 1850 (as I recall), who was on the hulks later, and was then pardoned just before the convict transport left - and just a few years later he came to Australia voluntarily and became a successful businessman (well - his conviction was for forgery and uttering ...).
Regards,
JAP
