It won't be self fertile - holly plants are either male or female, and you've apparently already established this one is female (I've not checked), in which case, a male is necessary. If your neighbours have a male holly, that'll do the trick, or if there's one in the vicinity somewhere. The seller has given you disinformation (or maybe its misinformation, not sure) - either way, what he's said is rubbish.

I have not heard of a holly being self-fertile before, but, having just done a web search this one seems to depend on who you read and who you trust. For example, Gardening Express says that it female whilst Express Garden Shop (I don't think that they are connected) says that it is self-fertile! I don't know.

I've just had a look on Shoot - according to them, this plant flowers and produces red berries - doesn't mention whether its male or female. Curiouser and curioser... maybe he wasn't talking rubbish after all. Shall do a bit more research...

Okay, it is a female plant and does need a male within 300 feet (or was it yards...) in order to produce berries. I was just wondering whether they'd managed to produce a non dioecious version of holly - but they haven't.

Not in the meservae group to my knowledge but Ilex aquifolium does have some self fertile clones such as J. C. Van Tol, Golden Van Tol and another the name of which escapes me for the mo.

Well hello stranger! Thought you'd emigrated Fractal, lol - Blue Angel is in the meservae group... Full name Ilex meservae 'Blue Angel'.

Lol, still here :)