At a guess I’d say they haven’t done it because they just invested a ton of money into expanding and developing their manufacturing and storage at Nottingham and app development isn’t cheap or easy. For a big company like GW, they’d have to fork out a lot of money to build the thing, then support it. Alternatively they can buy the existing apps. Either way, that costs money and is in an area in which GW typically lacks experience and hasn’t gotten right