zokissima: have a look here http://www.currys.com/
You may be within walking distance of one of their stores.
They have a really good selection of Iwata's and
some Badger and Paasche.
I'm sure they will have everything you want if you want Iwata - and no duty.
For Badger, I would go here: http://www.webairbrushes.com/
They have a wide selection of Badger and Omni and provide top notch service for Badger or Omni parts as well.
To do research on their relative spec's. go here for Iwata http://www.iwata-medea.com/products/index.jsp and here for Badger/Omni http://badgerairbrush.com
Rich