[...] My ADSL is 1:20 Mbit/sec upload:download, so a single coin with forked peers can saturate the upload side, and slow the entire link.

I've disabled HYP for the moment.
You could connect exclusively to a known good peer, so that you can continue to participate on staking and temporarily avoid the spam from outdated peers. To do this, remove/comment any addnodes you might have on the conf file, and have instead:
connect=104.131.135.232
I don't know if the "connect" command accepts more than one node.
If it does, you can also include these additional ones:
connect=192.241.233.70
connect=162.243.151.111
These are some of presstab's nodes. By connecting exclusively to one of these, you know you're on the right chain, as well as you prevent connecting to the outdated peers.
Happy Staking!