Have you thought about using the existing power outlet and expand with an adapter then it's all out of sight and only a few cables running into it.
Plenty available here:
https://www.ebay.co.uk/sch/i.html?_osacat=0&_odkw=12v+car+power+adaptor&_from=R40&_trksid=m570.l1313&_nkw=12v+car+power+splitter+adapter&_sacat=0