@Jonny *****
π - if you do work with a gallery get them to write a letter outlining your relationship and how it works (eg, the commission rate, how long you've worked with them, the amount of sales you make in a year, and their commitment to continuing to show your work etc). As some people in this comment thread have shown, people don't really understand how the arts work, so you really just have to be clear about how it all works.