EEA FP: One way ticket

Has anyone had any experience of entering the UK on a one way ticket using an EEA family permit?

My friends partner is coming to join her Irish citizen partner on a family permit later in the year and they'd like to (ideally) buy a one way ticket from the Philippines.

I have - three times. Nobody asked me for a return ticket.
Good luck.

One way ticket is fine no issues.

Thanks. Is there any specific legislation that covers this? I'd like to pass it on if such a thing exists.

There is no specific legislation. Airlines and immigration are aware of this entry clearance visa for uk and they will see it on remarks EEA FP FAMILY MEMBER TO JOIN OR ACCOMPANY
so no need to worry about it.