Hell or heaven, I don't know, never been in either yet. But it certainly works in 'my' church. Signal penetrates two walls very successfully, and 50m away and thro' a third wall it's useable - just.* So, success: we don't need to move the master socket: that saves us a few quid!
Thanks again for help.
*... however, the signal from the Weatherspoons a few doors down is a bit stronger than that. If I were feeling norty...