As you may have seen, Merlin have recently submitted a planning application to Solihull Metropolitan Borough Council for an activity centre type attraction to be located in The Pavilion which is a part of the Birmingham NEC. The planning documents state that it will include indoor skydiving and a high ropes course with zip lines, as well as a number of other indoor attractions.
The attraction is set to cost between £15 and £20 million, although there doesn't seem to be any time-frame given for its opening at this stage. The plans show off the fairly impressive exterior theming, which includes a large helicopter at its entrance, as well as giving an indication of the interior layout. The attraction will operate pre-booked slots with the main experience consisting of four 30-minute activities, with the option to then add-on additional activities afterwards.
Here's an article from the Birmingham Mail with a few further details.