I dunno what it is with the site but some area's look like they belong to other websites. They look like they dont belong together for some reason. For example you have the images page which looks funky (Apart from the nav) and then you click on and are displayed with a huge yellow page with a youtube video which looks apart from the site. I dunno it might just be me!
I suffer from epilepsy and that nearly got me going!
You have some really nice work in your portfolio, the site doesn't do it justice at all!
That navigation font is awful! whoever designed it should be shot!
I'd avoid using a graffiti style font and just use a solid bold grunge font.
e.g: You Are Loved Font | dafont.com
also possibly black and white the background image on homepage and use a bold white border around.
maybe bright pink type for active/mouseover navigation and white type for other nav
finally... I can't see any link between your nice typographic work and illustration and the banksy style you're going for... which IMO is a bit outdated.
the graffiti you have shot also isn't that great check out graphotism for some good stuff