Last week I used the DTCI at Terminal 3. There is a lot of construction that makes it nearly impossible to find the entrance because the airport authority won't let Virgin Atlantic put up a sign because it may appear to be "advertising", so stupid.
After arriving at the Upper Class Wing it was quick, efficient and I was heading for the private security within a minute of arriving. They greeted me by name and handed me had my 2 luggage tags and my boarding card.
It was worth the 19GBP to use London Heathrow Cars to drop me off from the Novotel Heathrow Hotel.
Here is a quick video of the DTCI..
http://www.youtube.com/watch?v=1aT4N...ature=youtu.be
Steve