Cheers m_c, looking at the data sheet for the bearing which is SKF6205, single row ball bearing, I can only see basic static (7.8kN) and dynamic (14.8kN) load ratings, not much about axial load though. Following your suggestion of 10% that would be around 0.8kN static, whatever that relates to in spring / compression force.

I've found some suggestions on Practical Machinist for using an o-ring as retention. One needs to machine a groove in the housing to fit and compress an o-ring and this should be enough to hold the outer ring in place. As this is a low speed application (max 300RPM) it might actually work.

Regards,
dsc.