I am planning to get my china visa at BKK chinese embassy, and holding British National Overseas BN(O) passport as i was born in Hong Kong, with one single entry china/shenzhen visa before.

Some agents suggested me to get a 'homeland return permit' as i was born in HK and it's more easy for me to access to china, providing it's much cheaper than a tourist visa and it's valid for 10 years, but i will not be in HK for the coming weeks and i am heading to Shanghai on 23/10, therefore i would love to get my visa done in BKK, if it's possible?

many thanks!