Hey everyone

I have 2 staffords, 1 is my girly who is perfect in every way, dog and people friendly

my 2nd is a male staffords who is well trained, obedient and absolutly loves children!
Only problem with my boy is he really doesnt like dogs which are bigger them him, smaller dogs he is fine with... when he was 6 months I let him off lead with 2 boxers, AFTER I had checked with the owner, are the dogs safe? as I didnt want my pup getting hurt, the lady said 'of course their fine' so I trusted her and let my boy off to have a play.
As soon as his lead was off these 2 boxers were dominating him, jumping on him and being aggressive, I didnt have time to fly at the owner, it was all I could do to pop his lead back on and walk out of the park with her 2 boxers chasing us and being horrible dogs in general.
Since this he wont let any dog go near him or my girl

He is getting slightly better but no one will help me socialise a 2 yr old stafford who is built big and is very powerful for his age.
Im worried whenever I see another dog off lead incase it runs up which they always do, and my boy swings round on his lead protecting himself and will NEVER let a dog approach him from behind, he shows his teeth but doesnt growl,maybe a little lunge if they get too close but if they keep getting closer (IE the owner will not call them back or cant even with me pleading with them to do so) he gets all skitty and afterwards tries to get away as fast as possible.
What can I do if no one will let me near enough with him to socialise him?
I hate thiswoman for what she has done, why cant people be honest if their dogs arent trustworthy???
All this bad press has really effected peoples attitudes towards staffords, even though my boy was the perfect puppy until he was set upon by these 2 large dogs

Who says staffords starts the fights eh???
Any ideas anyone?
Im afraid to take him to social classes as I dont know how he would react, he is fearful dominant from what I can see.
Its such a shame as he is champion bred and I wanted him to show, but I have no hope as I will be chucked out in a milisecond for his fearful behaviour.
Please Help!!!