Testwikidata is getting spambot hit, and pointlessly. We turned off direct account creations for wikimaniawiki (T247185) and it has been hugely effective for stopping the spambots.
Creations
https://test.wikidata.org/wiki/Special:Log?type=newusers&user=&page=&wpdate=&tagfilter=
Abuselog
https://test.wikidata.org/wiki/Special:abuselog
Can I suggest that we should replicate that task as there is little need to create a SUL account at testwikidata. We can create a direction for the account creation back to wikidata, similar to what was done at
https://wikimania.wikimedia.org/wiki/MediaWiki:Loginprompt
Accounts can be created at [[d:Special:CreateAccount|Wikidata:Create Account]].