Limit to subdomain

[davehardyuk]

Is it possible to limit external-dns to a particular subdomain?

Ideally I only want external-dns to manage the DNS for domains that end in test.domain.com i.e: thisisa.test.domain.com

I have tried (using helm chart):

regexDomainFilter: "(.*).test.domain.com"
domainFilters: ['test.domain.com']

But the external-dns pod wither doesn't make any changes or it reports everything has been updated. No DNS entries appear in cloudflare.

Any help would be much appreciated!