Hi Luke,
welcome at Stridaforum 
Just days ago Iāve published a short article which is referring exactly to your issue - just in German:
faltradforum.de/weitere-f77/ ā¦ t5025.html
In short words; it is definitely no problem to source those small bearings - BUT you need some special tools explicitly!
Either you use the original tools as below or you try a common āblind bearing pullerā of matching size.
Unfortunately is the bearing change most likely the worst issue which can happen on a Strida and Iād recommend highly to hire professional help.
Of course I can tell you how that works - however do not even try without the required tools 