I gave up, shut down the pfsense router & returned to using the previous setup (Spark's HG659b). This morning I tried again, same problem, still couldn't figure it out. Then after an hour mucking around pinging & ponging & looking (but not changing) stuff in both pfsense gui & my laptop's terminal it all came right without rebooting or changing any settings. I reconnected my switch, wifi etc. & all seems well. But it bothers me that I have no idea what happened (maybe I'm blind & changed something inadvertently). I'm very much an amateur, but presumably PPPoE discovery & recognising the router's MAC address had already taken place, so why the delay? This was a pretty vanilla setup, firewall was default allowing stuff out originating on the LAN, DNS Server settings were as per the old router, DHCP was always enabled & there was only the laptop & pfsense router at my end. So my question is, for those who know much more than me, is this likely to be something at Spark's end that was so slow, or my pfsense box (its not virtualized, amd64, Intel Pro/1000 nic etc.)?
Without wishing to recreate whatever mess I was in, can anyone tell me what sort of steps I (or anyone else in a similar position) should have done to isolate the problem?