When I bought my Wren the starter fell off on the third flight jamming the engine so I sent it back under warranty.
While it was being repaired I had the new integrated FOD screen/starter holder fitted & I think they sent me back
the original starter holder & the three supporting legs for it which I have no need for.

The Jet Joe was a Wren copy so these parts may fit, if you pick up the postage (from Oz) you can have them if
1/ I still have them & 2/ if I can find them.

A friend had a Jet Joe around that time, I think JJ used something cobbled together from hose clamps to mount
the starter. His engine was never really succesful in a Boomerang intro, replaced with a Jetcat P-70.