As potty an idea as I have heard in a long while. They will still need the same number of controllers as they do currently, so there will be no cost saving in terms of personnel costs. Until someone decides that, as the staff are not overworked on the LCY duties, they can control somewhere else in between flights.
They say they have connected the airport to (presumably) Swanick via 3 different fibre cables. So, do they own those cables? If so, there will have been a huge outlay on digging, routing, laying etc attending the cables. If not, and I suspect this will be the case, they will probably end up renting time on the cables from BT. And I know from experience that data to and from London can be routed via a 3rd point. And that 3rd point could possibly be on a different continent! Unless you pay a premium to guarantee a shorter routing. I have known data links between 2 points a couple of miles apart within London to be routed via Chicago during busy periods. So, presumably this will add to the costs in order to avoid the long delays, gaps etc.
It is claimed they will have 14 CCTV cameras plus 2 more with pan, tilt and zoom. That doesn't exactly smack of great flexibility.
Getting rid of the existing tower gives no extra space at the airport as it will be replaced by an even bigger one.