Mobile black economy?

I came out of the tube at Tottenham Court Road station I was handed the brochure below. I couldn’t work out if it was a legitimate business (though why would you go into a business against the likes of Carphone Warehouse and Phones4U?), or someone doing it from home as a kind of ‘under the counter’ business to skirt the tax authorities.
Mobile grey economy
I was amazed at the low-fi nature of the brochure.