I am a recently qualified electrician and I am looking at my first job and panicking a bit....

I have been asked to connect a under flooring heating system and a small shower pump. I am not sure of the wattage of each but they are both quite small ones)
I need to run these from a socket which has a 16Amp breaker (at the moment there is an immersion heater which connects via a ordinary 13Amp plug) . I am not sure if I can just spur off the socket to connect the under floor heating and the pump. Can I connect two spurs from this one socket

not sure if anybody can give me some advice on how to go about this.