Dear Allan,

> Anattarakkhita = Defender of Anatta?

No. Anattarakkhita is the opposite of attarakkhita,
'self-guarded'. So it would mean 'not self-guarded'.

A person who teaches anattaa, or accepts it, or defends it
in debate, would be an anattavaadii.

Best wishes,
Dhammanando Bhikkhu