See herein lies the problem in a situation like this.
The OP states that she wasn't offered a different room
Wringford say she was
Where is the truth?
OP you say you offered to pay the amount that Wringford said you would have to pay if your husband didn't come 
Wringford have said quite clearly that you were offered a smaller room, as there was only you and your child, but you declined.
With regard to the specific incident of your child going into the room, first off why was your friend "telling" the child to go there - to give you peace, to let the two of you chat, to have a drink?
FWIW In my opinion, if your child has hearing loss, then you NEED to keep them within your sight because if you need to communicate with them quickly for some reason you can't shout - I know, DS1, who is now 20 has severe hearing loss.
You should've been watching your child at all times.
And it does say very clearly on the website that area is out of bounds.
As to your other various complaints, most of which I have to say Wringford have answered, you could've found five minutes to speak to someone any of the days. If it mattered that much to you at the time.
Very odd to not raise any of these issues until you were checking out.
Also, Wringford has said that she didn't bar your way when you were leaving and has described the layout and how she was positioned.
How did she or anyone else actually try to bar your way out of the establishment?
Oh, and where was your child when this was happening as Wringford could not see them