Hi Mel,
Thanks very much for your insightful feedback. It seems that the LS3/5a can indeed be enhanced with the help of a sub, provided sufficient care has been given to integration.
I am also not looking for huge amounts of bass, just ‘as much’ to fill the missing bottom end.
I have asked a friend to come over with his equipment and measure the room. I hope we’ll be able to figure out what’s needed first. And we will keep a record of the before and after, so that we can compare.
Thanks again.