Heathrow Spotting

I know that the subject of the Heathrow viewing area being closed has been spoken of a lot recently, but I have a different question.

Is there anywhere in easy access from the terminals where you can get good views of the landing/departing aircraft without any hassle from the security, and also do any of these places have anywhere to sit or shade?????????????

I am either going to Gatwick or Heathrow tomorrow on the train but I am not sure if it would be worth trying Heathrow.

Also does anyone know if when the aircraft are landing on runway 26 at Gatwick whether you can still get good views of them or does the terminal obscur the views?

Thanks