At the core of it, there is no evidence that a Pavlos Maros claim to reality is necessarily existent.
This is actually technically correct for those of us who only know him on the Internet. As the old saw goes, "On the Internet, no one knows you're a dog." Pavlos could be a construct by someone quite remarkably different, a fictitious character, basically.
However, we could hop a plane, fly to the UK, and meet him which would then provide very solid evidence. Pics, videos, audio that corroborate what he says about himself would be pretty good evidence, too. Testimony from someone we know personally who has seen him in the flesh would be good as well.
But we can define Pavlos without all that, just based on his posting history here. Is that definition evidence of existence? No. Could that definition change when we collect that additional evidence? Sure. I would be surprised if it didn't.
And I would say right now, we have as much evidence for God as we do for Pavlos, and don't have the option of getting that better evidence, at least in a way that would be empirical and objective. Most people's experiences of "God" are subjective and an interpretation of something that happened, rather than something that can be shared with or replicated by another person (like meeting Pavlos could be assuming he exists). But we can still define God based on what we believe about God and those subjective experiences, without that definition actually providing any evidence that God exists outside that person's subjective experience. And others can share, discuss, and use that definition without objective knowledge of God's existence, just placing trust in that first person's subjective belief and experience.