Are 60 Day Tourist Visas Currently Available for UK and AUS Passport Holders?

Getting a tourist visa in Cambodia was a challenge in the best of times. I imagine it'll be harder now, especially since you were doing the passport switching trick. You aren't out of nothing trying, but it will take two business days for them to do the visa, if I remember correctly.

Once you get the visa, you can try to return. Traveling by air will require the insurance. Its unknown if the insurance will be required to return by land though.