Found this deal at the Gateshead MetroCentre branch - either one pack for £1.57 or two packs for £1.50(!)
Double checked at till and was verified - the kids love this stuff so its not a bad deal. I believe Morrisons were also doing a deal with these: single pack for £1. So its not a bad comparison deal.
Checked online and the deal is available for all kids yoghurts - two packs for 1.50! I guess some better combos to be had with this deal as some of them are more expensive than 1.57.