Any of the thumb latch catchers from the power torque series (eg Vortex/ Mustang) will fit on but your Rover solution is a handy option if you can't find any of those without some sort of damage.
The Rover catchers seem much more crack resistant which is a plus for going that way.

Have you seen this model before?

Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!