What does it mean when a woman says you're boyfriend material?

It doesn't mean anything, it's a meaningless phrase. People say silly things that don't mean anything, this is just one of those things.

So I am best just ignoring it or should I bring it up in conversation?

If she said your boyfriend material then to me she meant that she doesn't see you as a hookup but something more like a potential boyfriend.

I was speaking to my friend the other day, we have known each other for ages now and our conversations have started to get a bit flirty. Anyway she joked about any guy she sees on a night out being a potential hook up, when I asked her am I a potential hook up she said I'm more boyfriend material.

What does this mean and should I take it as though she meant it seriously?

I think - and this is just me - that the hook ups are one night stands and the boyfriend material is a much longer prospect.

So that's good for me then, I do like her so do you think I should bring it up the next time I speak to her?

yeah you could just be honest with her and tell her how you feel. Or you could wait a little longer till you flirt more and become closer then bring up it.

So I am best just ignoring it or should I bring it up in conversation?

as a woman with a boyfriend who had a crush on me for many years I can say that "you're boyfriend material" was used in a jokey but flirty way. She wouldn't openly admit like 'hey I like you', but it's a nicer way to joke around while telling you she likes you. She is giving you a chance to act on it if you wish.
It's a clever phrase because it gives you a choice.
You can act on it, flirt with her and see where it goes
or
dismiss the comment and see it as a joke and it isn't threatening to anyone's feelings.

The beauty of it

So there is a chance she likes me then? If so then I am going to act on it because I really do like her.

you just got friendzoned