rcd current

Hi all, woke up this morning to a buzzing and crackling sound coming from one of the sockets in my bedroom when I turned it on, which also caused the lights to flicker at the same time, what is the 2nd socket inline on the 20A radial socket circuit. Stuff was not working/powering up on this...

Planning on purchasing an i3 and looking at charging solutions as an interim until I get a charging point installed on the front of my house (as will need drop kerb fitted by council). I have a garage at the back (about 20-30m away from house) and was planning on running a 2.5mm diameter run of...