Hey mate, have you applied a blank design/layout to the search page and viewed the source of the results page (to check for any lingering Squiz div code)?
If so and it still brings in design code, check the settings to be extra sure there are no design/layouts being called via URL or some other condition.
Finally, I usually configure a site’s settings/layouts screen to use a blank design/layout combo in new User Defined settings. Once set up, add these values to your request object, where XXXX is the user defined code you used:
SQ_DESIGN_NAME: XXXX,
SQ_PAINT_LAYOUT_NAME: XXXX
You can also set up a new design code for JSON too: