Engr roulement LADs

So 38 and 25 were going to swap Ripon for Antrim. Were the LADs staying put? Now 21 is moving back to the Catterick area Ripon has been mentioned. How is this factoring in? Are all the LADs staying insitu?
This is (nearly) the most waste of money I have ever heard of. Why dont they just re-role? Engineers get posted around their units anyway...