You can buy replacement 'lighter' sockets for less than £3. If its replacing a faulty one most of the hard work is already done -such as cutting a hole ,wiring etc (although sometimes you might need to attach the wire by soldering. )
They can also be used to add a second socket,, which in some situations may be a better option than using twin socket adapters etc. But you have to be careful not to overload the wiring by running two sockets, capable of drawing 20 amps each, from just one supply wire.. You might take care not to overload the sockets but a subsequent owner might plug in high amp items such as tyre pumps, electric cool boxes etc .
https://www.ebay.co.uk/itm/336266233255?