If you get two of the screw in type power sockets a plate to connect them together is easy to make if you have a hand drill. A small piece of ABS, drill two holes insert the sockets and sceww down the retainers that come with them, done.
I made one a while back, can post the pic if it would help you. Use a piece if scrap from the plastics store, often free so no cost to make it up.