Fair enough, Dominic. Let me say I think there are two kinds of belief: conditioned (by others or oneself), and evidence-based. Think of it scientifically: the scientist constructs a hypothesis, and then tests it: the evidence may either support or refute it.
So what's the hypothesis? It's in two parts. First, that there's the possibility that life has some kind of meaning. The second, is that there may be a way of obtaining evidence to support that. If a person rejects that hypothesis out of hand, without testing it, well, that's their prerogative, but at that point further dialogue becomes pointless.
How to test it? Well first, I don't believe it's easy. It can take many years, throughout which one has to be genuinely open to the first possibility even though no incontrovertible evidence may be coming in. What is the procedure for getting the evidence? Maybe one can find a spiritual teacher and carry out prescribed exercises, for example: not that there's any guarantee, because there are many bogus teachers out there (and perhaps even more bogus students). Some think psychoactive chemicals can do the trick without years of striving. I'm not really qualified to say anything with certainty about either option. That said, I discovered inadvertently something that may have worked for me.
The very act of searching for meaning, maybe for several decades, leads to the discovery that one has disguised motives for doing so. They're egotistical: maybe one wants to feel special or to experience nirvana or whatever. So, one tries to kid oneself that this time one is being sincere, wanting to find meaning (whatever it might turn out to be), for its own sake. After going through loop after loop and discovering one is still being egotistical, at some point, despair might set in.
It has to be genuine despair, and that can't be faked. Despair is horrible, but it has a potentially useful side-effect: it puts a bloody great hole in the ego. And that's an important aim of genuine spiritual teaching. Zen masters have one way of beating pride out of you, Sufis another, Hindu mystics a third, and so on. And my theory is that when the bloody great hole appears, the conditions may be right for an enhanced spiritual awareness to arise: I suspect we'd be aware like that all the time if we were humble all the time, but few of us are: maybe only the very greatest of adepts are. I'm not saying that the awareness, if it comes (again, no guarantees) will be very dramatic; it may be quite subtle, but one thing for sure is that it'll be something one hasn't experienced before: and that's what constitutes the evidence in support of the hypothesis.
I've said that I'm an atheist of the Abrahamic God, and that conventional religion is not for me. That said, it wouldn't surprise me if some religionists might, through sincere faith, also develop spiritual awareness. The odd secular humanist might eventually develop it too. And there's always the (remote) possibility that even the most hardline materialist might have a Damascene experience: who knows.
So: I've explained to you the hypothesis, and how it can be tested. I've said it may take decades to get the evidence, and it might never happen anyway. Dismiss it if you want, but if you do so without giving it a try, there's no way you'll ever know whether it's bunkum. And if you do get the evidence, it will only be good for you: there's no way to convince anyone else.
It's a bitch, ain't it? The experiment's not for the impatient, insincere or faint-hearted, that's for sure.