This might seem ridiculous to people, but if this place in Kent counts as a London airport, what about BRU (Brussels) as an alternative London airport too?

I travelled from BRU-JFK due to a *much* lower one-way fare than from LHR last summer, and discovered that the 2h15 journey on Eurostar followed by a 15min local train to the airport (included in the Eurostar price since yoiu can go to any station in Belgium) was very convenient. And since the Eurostar is a train set up for travellers you won't find it difficult to stow your luggage...

The youth fare of £40 one way is less than a taxi cost to any of the London airports!