The Masterplan seems to be a 300M runway extension,and perhaps the Damon Hill stand (0).After that not sure.The helicopter areas are all leased areas,and are no go areas generally.That way the BAA don't have to snow clear those areas.
The helis are going to other places because they cannot be fitted into the circuit anymore.There is extra capacity at the weekends for training,but they don't want to use it.They are a severe pain in the backside,and a lot can't accept that they are at the bottom of the food chain.Just last night BND held for 50 mins in the ADN hold waiting for a gap for a procedural approach.
I worked there in the ''wonderful'' 1980's and it's as busy now as it was then.We have a lot more PC things to do now,so our workload is much higher.Then the whole thing descends into chaos,cos the BAA can't pour enough concrete,or the baggage carousel is jammed up.