Great thanks everybody! It's very much appreciated. I'm pretty sure that we won't be going to the DPRK anytime soon but I appreciate the tangent.
We previously moved her from Shanghai so she was microchipped there. I believe we can buy a scanner ourselves and as long as we have the correct scanner during transit it'll be accepted in the uk.
To make matters more complicated, we have three different pet passports due to traveling around China. Our current one is from Shengmei Animal Hospital 盛美动物医院 where she received her rabies vaccine etc. I don't want any more confusing documents so will be going there later today to try the next step.