OK - I think I have something in place to turn away the distributed spamspiders without interfering with members and guests.
Here is how busy the worker machine has been - overloading during the night, but with my tweaks doing better

And here is the day by day relentless rise. Days end at 03:30, so only part of the traffic from last night is yet seen - I expect it to look the same when I look tomorrow morning, but hope to see it eased off by Sunday.
