I suspect that the problem is that although PGT is the favoured trainer for a lot of people who went to Kemble recently, being a modular provider, everyone had to go and get a PPL first. I intended to use PGT but am only about 2/3rds of the way through my PPL (winter weater was rotten!).
The only students for the full ground school that they would have had so far are those with a PPL ready and waiting to go. There wouldn't have been many of those!
Late summer might have been a different story. We will never know.