I'm writing my master thesis on Travel Retail & Duty Free with a specific focus on Heathrow's terminal 3 boutiques. In order to visit this terminal and take pictures for my research paper I already spent some money on a flight to Paris CDG- which unfortunately boards at terminal 4.
Is there any way I could access the Duty Free zone of Terminal 3 prior to boarding my flight at Terminal 4?
If not, how could I access the post-customs Duty Free zone of Terminal 3? Whom should I contact?
NB: it's solely for research purposes, not to go on a shopping spree.