I order everything Doctor Who from Who North America:
https://www.whona.com/
Great prices and inexpensive shipping when they shipped USPS. I'm not sure how expensive shipping will be now that USPS raised their rates, they also offer DHL but I hate them since they left my DCD Superman figure faraway from my house in the driveway and left it there late at night.
There's also the Who North America Forum operated by the same owners of the store:
https://www.whona.com/
They might have more info on Character Options Who 5" figures as well as anything else Who related.