For anyone following my path Arne Saknussemm-style, patience is all.  Once the blockchain finished syncing (took about 8 days) now all inbound and outbound connections are working fine.  So maybe the core accepts connections, but doesn't respond to them, if the inbound height is greater.

So 2 days later and it is still struggling to sync, but getting close.  404621 blocks now.

Meanwhile I don't understand why I have so many nodes connected which are sending, but not identifying themselves.  I'm receiving blocks, because the count is slowly increasing.  Sorry if this should be a separate question.

Thanks all, will be patient!  Cheers

Thanks for the responses.

Yes, it is still syncing.

The IP is "reasonably" static   Dynamic, but hasn't changed for more than a week.

Bitcoin Core v0.12.1 64-bit, OS X 10.7.5

Steady 8 active (outbound) connections.

I used http://www.subnetonline.com/pages/network-tools/online-port-scanner.php to check that port 8333 is open (and port forwarded to the bitcoin workstation).

https://bitnodes.21.co *sometimes* says reachable, and sometimes unreachable, about a 50% chance of each.  (Huh?)

Debug window shows steady 8 outbound peers - when I hit Check Node at https://bitnodes.21.co I can sometimes see an inbound connection from e.g. 136.243.139.96 but it looks like my bitcoind is not responding.

Any advice warmly welcomed.

Should I post my IP here?

Thanks

Edit: this is the Debug Window during https://bitnodes.21.co "Check Node":