Some months ago I had a Tesco HL sweet chilli chicken noodles meal for 2 syns. I bought it again this week and double-checked with Syns Online. It's now 6.5 syns! Am I going mad or can anyone back me up? I have to wonder if SW have increased competitors syns in order to promote their own brand.

No you're right, SW says 6.5 syns.
Using the syns calculator, it shows as 5.5. I don't think they've increased competitors syns values, my guess is Tesco changed something in the product recipe maybe?

Yes Sarah, you may be right there. I remember going back many years though, my consultant said that competitors branded food will have more syns because it's not SW. Does that make sense? Anyway, I won't be getting them again!