Brentford has cctvStansted, Stansted Airport, Round Coppice Road, Stansted, Essex, CM24 1SF.
To take advantage of these prices you will need to prove you are a leisure traveller, en route to stansted airport, so you will need to give either your flight details or your holiday booking reference. I don't think you will need to provide this when you arrive at the station but you may be asked to give them on your journey from the station to the airport.
Going to the airport by train is great, you can take a nap, read a book (even at night), play travel scrabble, or just gaze out of the window... The other caveat to buying these inexpensive train tickets from brentford station to the airport is that there must be at least two grown ups travelling together. But another great advantage is that children go free. All children under five go free, and then one kidover 5 but under sixteen per grown up travelling on the train to stansted airport.
make sure you leave enough time to get to stansted airport early enough to eat, shop etc, so check the times of trains from brentford station before you go. If you end up with spare time at the airport you can always read or play travel scrabble again! As you have bought your train ticket in advance, you don't need to fret about the opening times of brentford station.
the station opening hours: Monday-Friday 06:30-10:30, Saturday Closed, Sunday Closed..