Hope someone can help.

Was planning on using one of my soon to expire Amex vouchers to take a holiday in Phuket in November.

My plan was to travel via Singapore on BA and then directly onward to Phuket via a local carrier (currently no reward availability to Bangkok with BA but plenty via Singapore).

However, having looked at the Singapore Airlines website, it seems to be indicating that passengers will only be allowed to onward transit if they have arrived on an approved flight (carriers such as Singapore Air, KLM, Lufthansa, Turkish Air to name a few) but no mention of BA!

I’m assuming this info is correct and my plans are void, but hoping someone may tell me i’m misinterpreting it and I can fly this route?

thanks in advance