This maybe common knowledge by now but just hasn't been talked about here.
Singha Light(3.5%) is now no more and has been increased to 4.5%(?) and has an all blue neck label.
The new variety is in the bars in Pattaya and the original is as rare as rocking horse shit in the supermarkets and is being replaced by the new one as stock runs out.
If your into it and it's still available in your area then maybe you should buy it up.
This topic has been well talked about on Thai Visa in their Farang bar section.