I read the thread first before watching the video and I cannot believe some of the comments made towards this woman - both by yourself and by others on this thread.
She was obviously grateful for the kind return of her son and bike and I can't see anywhere where she acted like a "bitch" or "witch". I was expecting a fag-smoking mother-of-five with a can of Tennants in one hand and a lead attached to a pitbull in the other!!
Now don't get me wrong, her son could have been killed by his carelessness and I can't see any time (on your approach) that he turns to look up the road before crossing it. Which, as a parent myself, I find quite shocking!! He has been a very lucky lad indeed to have only had his wheel damaged and a few bumps or bruises, and he needs to be educated as to how to cross safely when he's out and about and maybe even advised to walk his bike across busy/fast roads.
I also feel for you because most of us also know how frightening it can be to hit things or be knocked off -it can be bloody scary stuff - brown-pants moments are not uncommon when you are a proficient and fast cyclist, but they do tend to leave you on edge a little afterwards, so I'm taking a guess that you were still a bit wound-up from the incident when you arrived at his house?
You did a very good thing walking him home and ensuring he was safely back in the arms of mum 'n' dad - especially when none of it was really your fault - however, from the video you appear to have turned up at this woman's house, with the full knowledge of what has happened, and started ranting about compensation and arguing with her. She has understandably become defensive; I expect I would be. She doesn't know you from Adam and you're making out like you might want something from her (seriously, listen to how insistent you are being with her). She hasn't seen the accident and you're throwing in a figure of £1500 quid. I can see why she's been unreceptive. She also possibly wants to make sure her son is okay and get his side of the story too (and maybe even give him a bollocking for being so careless?).
It might be best to remove the video from YouTube and make a more measured approach to the lady. Call round and calmly ask if you can come in and show her the video, so she can see what has happened for herself (she might well be quite shocked by it - I know as a parent I would be!) - and then explain that you were just wanting to have a general agreement from her to pay for any minor repairs that you might have found later.
I understand how you feel but I think the approach to resolving it could have been better.
Anyway, I really don't want to see any more name-calling of this lady on CC please.
Thanks,
Shaun