I figured it hadn't a clue but couldn't work out why it was all going to hell. What I've done now is to move the 2nd one (here, it was high up and while you couldn't see it it was in the open - not IN the cupboard ;) ) to a different room, where there is another switch so I could plug it in. SAme details as the other one so I am presuming my devices will swap from one to another depending on signal. The coverage is really just needed to get to the garage which is away from the house. The original point is as far away from that as is physically possible!
Just thinking there that the usual 10/100 card that was teir originally would have been fine for the 72Mbps connection. I did replace the PCs in the house onbaord cards (and the pfsense cards) with 1GB just for internal traffic - a lot of file shifting going on.
Thanks for the help.