My 15 year old is travelling with me to the UK in 6 day's time, returning mid-January. We are travelling on New Zealand passports and will be stopping in Japan for 2 days. I have just noticed that his passport will be 20 days short of 6 months from expiry. Does anyone know if he will he be able to enter Japan and the UK? He is British and I will travel with his birth certificate. Or shall I try to get a renewal urgently?