So I've just started playing this and have been told to find the Mayor in Seaside Retreat, but he's not there.
I'm pretty sure I'm at the right place, see attach image, and have searched everywhere that I can but I can't find him. So I started a new game, rushed though it, but still no Mayor.
Is there something that I need to have completed first?

Well now I feel a bit silly, lol.

Had a read of a walkthrough and it turns out that there was more to do in Squid Baron's Labyrinth. I had gotten the new dance tranform(monkey) and had left, forgetting all about Squid Baron. So after going back and fighting him, the Mayor now appears.

New Life lesson: Never forget old enemies, even if life gives you monkeys ;)