Thanks for your quick reply.
Sorry if it seems obvious, but I'm afraid that nothing to do with internet/broadband speeds is obvious to me ! 😉
Maybe I didn't explain properly. The ethernet homeplugs are 500Mbps rated. So to get more than 100Mbps through the gigabit plug I need a 1000 Mbps homeplug at each end rather than the 500 Mbps plugs I have at the moment?
Thanks again.