Hi Tom,
Knowing the strict security protocols in Singapore, I don’t think they would have allowed anything illegal to continue operation for such a long time, seeing as some members have been using 868MHz modules there for quite a time now. But I’ve also seen some manufacturers marketing their 915MHz range for Singaporean market and again I don’t think that’s strictly illegal.
Both these should be in Singapore ISM band but that’s about to change as far as I’m aware.
I wanted to contact Infocomm Development Authority of Singapore (IDA) but havent had the chance so far; perhaps they wouold know?