Hi Roger,

Thank you for your question. visa on arrival works for UK British citizens (either living in UK or France or anywhere else) visiting Vietnam either for tourism or busines purposes so surely you can apply for a visa on arrival for your family. if your children have dual nationality, you can choose 1 as their nationality and just make sure everything must be consistent, if you apply for a visa on a French nationality, at the airport you will need to show off your French passport and so does for the UK passport.

regarding the procedures, all you will need to do is to submit an online form for the letter of approval to pick up your visa at airport. the very first step of the process will start here. hope that helps.