Hotpoint Aquarius 1100 Dryer very hot even on low setting?

My Hotpoint Aquarius 1100 washer dryer is drying the clothes, but its very hot even when being used on half heat. Its also making a noise when tumble drying, like a grinding noise, but theres no noise when washing. I suspect it may be a thermostat problem, but I don't know where its located or how easy it would be to change.
Hope someone can help! cheers,
Tony.