I've been talking to this guy for a while, who is a good friend of two of my friends, however I have yet to actually meet him. He knows I have anxiety so he has left it up to me to arrange to meet, and initially I thought I'd meet with one of our friends there but I don't know if that's possible now. I know it's irrational anxiety but I am so scared to meet up.
It is not irrational and I totally understand where you're coming from. It's good that he's left it up to you to decide when/where to meet, he's obviously very understanding and it's great that you're not being pressured into meeting up. So now you just need to find the courage to actually plan to meet up with him. You should meet somewhere public and somewhere that's familiar to you and where you feel comfortable. And if you feel better bringing someone you can bring another friend, it doesn't have to be someone he knows. But just try to remind yourself that there's nothing to be worried or nervous about. You're just going to meet up and hang out with a friend! Once you do it, you'll be so proud of yourself for overcoming that anxiety.
Good luck!