Can anyone here tell us how to transfer 150k THB to a Hong Kong account?

Go to your bank tell them you want to transfer 150K baht to HK, fill out forms with swift code HSBCHKHH .

Max single transfer is equivalent of US$25,000

Cannot transfer THB out of Thailand unless you have work permit. If you have work permit, you can go to the HSBC branch on Rama 4 and they can do it for you from there. Its the cheapest and easiest way to do it. I also have HSBC account in HK.

Thanks. No work permit. Didn't think it would be a problem such a small amount.

Local bank says need evidence of wht its for - family details/ invoice etc.... but its just going to an investment account.

I hold an HSBC account in KL. My wife does the transfers through SCB, the first time was painful as they wanted to know the ins and outs of megs as-hole. Subsequent transfers have been no problem. And yes, they do want to know what it is for, the most common reason used is 'family support'. You do of course need to have an address in the country you are sending to.