The connector plates are made to be on a regular flush box. You could surface mount. Use a deep box though. There are boxes made for the job https://www.bes.co.uk/35-mm-patress-box-white-22071/ EDIT…Actually (I’ve never done it) there’s nothing to stop you just screwing the plate to the wall, no box needed. You’ll see what’s possible when u get the plate. Feed cable comes into the top of the connector. The outs come out of the bottom. Of course you can loop the 2.5mm cable, supporting the cable with clips, of course. You won’t see it behind the cupboard.