Hi Graeme, I had a '48 Ute that did that from time to time, found that in 3rd gear you could usually get it to retract rather than using 1st. Also ended up leaving the end cap off the oilpan so you could get at it with a big shifting spanner or multi grips ( probably get scolded for calling them something that's not US speak
)......and then it was a simple task to wind the end of the starter backwards and that'd pull the drive back out of mesh with the flywheel....