Using a PC based flight sim to keep up your skills is one thing, using it on your own to try and learn the skills quite another.
Pace, I hear about schools like that and I understand why so many people who have sat next to me in an aircraft have been so poor. It isn't their fault, but it is they who pay the price for shoddy training.
Smart youngsters can often get away with dodgy training, the general PPL population can't and this one of the reasons that proper GA flying is relatively rare in the UK. People simply don't have the skills or real confidence to go off and challenge themselves and that makes me very sad.