When I did my police check, they required my ID and nothing else. Of course, I did it locally, so it wouldn’t have made sense to require a passport.
Yeah, you need your ID if you’re a citizen with HHR. For NWOHR, I’m sure you need your TARC, but you can always call and double check to see if they can make an exception if you don’t have yours on hand.
I still have my ARC from before I was granted citizenship so I might just apply with that and my ROC passport and see how I go
If it’s still not expired yet, then you might be able to send that to them with your other foreign passport, and they’d be none the wiser. 
Might not work if they communicate with the NIA though.
Just wondering if this is correct?
That’s what the instructions seem to say. It’s only $7 US so it should be fine.
I’m in the process of doing this, also living in London too (I’m an Australian citizen with an Australian passport only)
Wondering if you can give me the details of the notary you used? Does the Taiwan representative office in London accept Authenticating Australian passports or would it only accept UK passports? Also not sure if FCDO would be ok legalising a foreign passport…
So I may need to get this done back in Australia… but any help / guidance is appreciated
Mine finally arrived today.
My situation was a bit all over the place:
Things dragged on for me because, back in January, the FCDO incorrectly told me they wouldn’t legalise a photocopy of a foreign passport, even if it had already been authenticated by a UK solicitor.
I also rang the TRO office in London, and they kept directing me to deal with the Taiwan office in my home country (Australia), while the TECO office in Melbourne insisted I should handle everything through the TRO in London. Typical.
In the end, I emailed the FCDO again a few months later and got completely different answers. After a lot of back-and-forth over phone calls and emails explaining my situation in detail, I decided to just proceed.
I asked a friend of mine who’s an SRA-regulated lawyer in London to sign and stamp my passport copy. I then sent it to the FCDO for legalisation, followed by the TRO office in London. Everything went through without any issues.
After that, I posted off the letter to Taiwan, and it took just under three weeks for the police checks to come back.
Glad it’s all sorted now and hope this post helps anyone else going through this situation.