Hello Carll,
If you check the FAQ Page, if the part number is not listed, the item should be recycled using your municipal recycling programs.
On the UK Xerox Green World Alliance page, when I select our MFD, which are WorkCentre 7800 series, the toner cartridges are not listed against the recyclable consumables, so presumably not eligible for a Cartridge Return Label Request?
If we had a Xerox ECO-BOX, would toner cartridges be permitted in that.