I have to wonder why these three aircraft did not get retuned to RAF service and speculate that a still metal-centric RAF contractor failed to understand that these aircraft could be repaired economically and continue in service.
More likely that the gliders were uneconomic to repair on paper. For the company that did repair them to be able to do so at their leisure when other work was quiet, and possibly with access to serviceable airframe parts from other damaged G103s to cannibalize, is a very different situation. Think of all those Cat C and Cat D cars that go back on the road despite main dealers having said they are beyond economic repair.
Even if the gliders were only repaired and sold at cost, the opportunity for future spares and maintenance support might have made the return to use cost effective.
What must not be ignored is that composite work in the aircraft industry is a growing market and that skills and experience in this field are in very short supply. Many of the glider repair companies have found that manufacture of composite sub-assemblies to aircraft standards (e.g. for motor racing, submersibles, wind turbines etc. ) is a more lucrative business than fixing gliders. Any organisation that thinks it can jump in, pay bottom dollar wages to people with no understanding of these aircraft, how they are made, repaired or used, and make a success of it, is both deluding itself and the customer.