He is pleased the decision to send him there has been vindicated despite the doubts of fans who thought he would get a rough reception at the Den, and he says:
"At the end of the day the boy is there, one to gain experience from our point of view but two, if he is holding a place down in Millwall's team, he is doing a massive job for Millwall Football Club.
"And while he is there, knowing him, he will give nothing less than 110%, as that is the sort of boy he is.
"He desperately wants to win and while he is wearing their shirt he will want them to get a victory in every game he is involved in.
"You hope he can cope, which is the whole reason for sending him there, though I wouldn't say it is a surprise that he is doing so well.
"But there is comfort in the knowledge that our assessment of him being able to do so has been reaffirmed with his performances.
"It is pleasure that he has been able to go in at that level and take to it immediately without any experience of league football.
"The whole time he is there he is going to gain invaluable experience, but when he comes back in the new year - if not before - if Glenn feels there is an opportunity, he wouldn't hesitate to put him in.
"That is the whole idea of him going there - it goes half way towards answering the question of whether he is ready to go in our first team, and I am sure when he gets the chance he will grab it - he has made terrific progress.
Glen started his way up the ranks as a centre half but Tony explains:
"You look at Glen and you think his position at the top grade will probably be at full back; he hasn't quite got the height that one would have hoped to play centre back, not that he couldn't fulfil that role alongside a bigger centre half.
"But we feel that long term his best position is at right back, which, after all, he is filling admirably at the moment with Millwall, and holding his own in the first division at only 18.
"We watch every game he plays in between us and we have been very pleased with his progress."
Glen is currently in the second month of a maximum three month loan.