Superpilot, thank you.
I changed the DNS Server settings as per your piccie. Thanks for walking me through where to find it.
Initially disconnected all other devices, rebooted and it is working well now, including from other networked computers, and wireless-connected iPad.
Here is my theory (which may be rubbish, because my wife tells me to stop self-diagnosing and telling the doctor what is wrong with me, and rather just describe the symptoms and let him diagnose).
I think it's a service provider problem. We have had floods all through our state, and I think they have some service issues. I am connecting to other servers at good speeds. I would liken this to the following example: my 'old' route has become flooded and the data was forcing it's way through the flooded creek; we now have a different route so the data is all getting through. This doesn't explain the 'no dropped packets' though.
Oh well, bedtime here, and for now I can sleep easy and say thank you once again, superpilot. I'll check again tomorrow, and through the weekend, and let you know if this is a permanent fix.