Unfortunately spectators are a very low priority on BAA/HAL list of to-do items. Although the call for a dedicated spectators area is on-going, it will never be inside the airport due to security reasons. There is a minimum fence and screen height for all areas accessible to the public, so viewing would be through a glass/perspex fence. The cost for re-enhancing and making QB roof back into a viewing area runs into the high several hundred thousands of pounds. Not viable. Then the arguement is, that why should BAA spend so much money on enhancing and securing the spectator viewing areas, when so very little revenue is gained from it.
I'm sorry but there will be no viewing gallery inside any of LHR, also the cost of running the Visitor centre is too great for so few returns, so close it to the public and turn it into a training centre. Sound business decision.
Oh, by the way, it's not security who patrol the surrounding perimeter fence but the local police. I do recall several weeks ago whilst waiting for transport near the northside, a lonely solitary spectator was perched on a ladder taking innocent pictures of the aircraft. I remarked to my colleague that I didn't fancy his chances when PC plod see him up his ladder. Low and behold, minutes later an entire van load of them decended on him, and gave him a free lift away from the area. So no more climbing of ladders either. :-)