One mistake I made you can see in this picture from when I first set it up.......
The wiring going from the immersion itself to the blue artic socket....... Change that straight away to artic 16 amp cable.
Now I've got blue artic cable to the socket from outlet, and socket to immersion.
I noticed it was getting a bit warm and started to melt.
Must be because I was using 16amp cable all the way till it reached the cable that came with the immersion which is 13amp.
Your son will keep you right though I'm sure.