I agree with Pobjoy.
I've stated several times in this thread, Air Cadets do not 'need' something as high performance as the Viking and a return to low performance in order to get the cadets to solo standard easier should be called for.
What do you suggest? In terms of modern gliders a Viking is NOT high performance. It's solid, robust, easy to fly, and has good crash protection - far better than the gliders of yore.
The BGA regulate with a very light touch.
From what I have heard the Vikings would be grounded even under the BGA's regime. If a glider doesn't have the correct paperwork, up-to-date, it's not airworthy. If it has repairs that are not documented it's not airworthy. If repairs have been done & documented but not to an approved scheme it's not airworthy. And so on.