As I've mentioned before, I'm a little uneasy about the rumoured takeover by AENA. They are a subsidiary of the Spanish Government, which is seriously bust (unemployment in Spain is 25%, youth unemployment over 50%; debts are enormous; the economy has been in recession for several quarters; tax receipts are down, etc). And because they don't control their currency, they have few options.
The hike in charges at BCN and MAD last year was a direct consequence of Spain's economic predicament. As David Johnson says, AENA has an effective monopoly in Spain, and is as a result probably not the most efficient airport operator in the world, even if the largest.
I hope AENA come to LTN understanding the intensity of competition in the London area, and are prepared to manage it accordingly. Gatwick is roaring ahead under new ownership, Heathrow (also Spanish-owned) is building on its unique position as the UK's only hub. Southend, whilst small, has nimble owners and Stansted is now owned by the desperate men of MAG who are probably beginning to understand that they have drastically over-paid for their chunk of rural Essex, and may soon start taking desperate measures.