I've got Boone and ED-C as two of my companions and ive just discovered Veroncia on 188 Trading Post. How do you manage to recruit her? because ive tried loads of different dialogue's and its not working? Any help/suggestions?

Beef

Kill Boone first!
Or you could just ask him to leave

You can only have one humanoid and one non-humanoid companion at a time.

So to take Vera you have to ditch Boone. To take Rex you have to ditch ED-E.

you will have to drop boone Boone to made your quota of (1 humanoid / 1 non-humanoid) companions

Even having Boone with him, he should still be able to get to some sort of "Why don't you come with me?" line, to which she'll respond something along the lines of "I would, but you seem to have plenty of company at the moment."

OP, have you gotten to a line like that, or is the problem that you can't even get to the offer?

(I'm trying to remember what I said to her, but it was basically friendly, tech-friendly, non-judgemental stuff. I may have already had a good rep with the Followers at that point, so that might have helped, too. Not sure what, if any, extra requirements there are to get good reactions from the different companions.)

Cheers guys! really helpful!

no it was more along the lines of going through the dialogue then fianlly it will always end up saying, i dont want you right now! then you'd click on her again and then the conversation would just end with her! so i got rid of boone and kept veronica