Trying to replace the bearings on a set of Giant PCX2 wheels but absolutely stumped about getting both end caps off together.

Is there a knack or something stupidly obvious I have missed?

I’ve removed one of the end caps (non drive side) and knocked the axle out of the wheel, but I cannot get the other end cap to budge.

I’ve had the axle in a vice, and tried to unscrew the other end cap but absolutely no joy whatsoever. Without this I’m kind of stuck getting the other bearing out…:-/