Perhaps there isn’t much demand in your Tesco. Store brand (organic) soy milk is 0.9€ here in Paris which is cheaper than the organic cow alternative - which is subsidized btw.

6.5£ for seems super cheap for beef and I’m sure tofu can be even cheaper when optimized. I find it here at the same price but it’s organic and grown in France. I wish it become more popular where you live so the prices become more competitive.