That instance's real url (at least in the DB) is lemmy.podycust.co.uk. parapheum.com is another one that has a similar situation, they have ~5k new accounts in the past days and very little activity on their instance other than the admins. I have sent messages to the admins of both instances making sure they are aware of the situation...

For fun here are the numbers of their users that show up on my instance (because they have participated somewhere my instance is federated with) compared to beehaw which has about 12.5k users:

lemmy=# select count(*) from person where instance_id = (select id from instance where domain = 'beehaw.org');
 count
-------
  3496
(1 row)

lemmy=# select count(*) from person where instance_id = (select id from instance where domain = 'lemmy.podycust.co.uk');
 count
-------
     6
(1 row)

lemmy=# select count(*) from person where instance_id = (select id from instance where domain = 'parapheum.com');
 count
-------
     3
(1 row)

Seems pretty concerning.