Morphy Richards new Intellichef, states boil at 240 degrees C?
You are correct that the indicated temperatures are too high.  240 C (480 F) is a very fast oven temperature, and inappropriate for almost all direct contact cooking methods.  Even 120 C is well past water's boiling point, and so not achievable in slow cooking.

A more typical an appropriate braising or slow cooking temperature would be 82 C (180 F).

Assuming this is the instruction booklet for the product you have, it appears the instructions for slow cooking are actually trying to get you to do a two part braise (they even seem close to identical to the braising instructions):  first searing the meat for flavor development through browning, and then a longer cooking period.  The higher temperature is intended for the searing phase; they then you have reduce the temperature to about 100-140 C.

This is still too high for braising, but that may be the temperature the device's thermometer will perceive at the bottom of the cooking insert.  You want the temperature in the actual food to be about 82 C&mdash;use an instant read thermometer to help learn where to set the dial.

Similarly, the boiling temperature is almost certainly again set too high (as water, by definition, boils at 100 C), with the intention of putting the device at its maximum power to bring the water to boil and keep it boiling rapidly.