welcome to the forum
Congratulations on your son's results!!!
From the Historical information we have gleaned, I would hazard a guess that you would perhaps be offered a place at SG.
Here is a post that will help....
It will most probably be about the same cut off for first round
Herschel may be slightly higher as it seems to be becoming more popular.
I think last year the last info we were given was..
LG 116 (some 115)
HG 113 (some 112)
SG 112 (some 111)
this is only by memory.... if I come across anything diff or someone else can correct me then I will edit the post.
Have a browse on the forum at the other threads, there is alot you can find out.