[Solved] Supervised Visits

Hi everyone,
I'm just wanting some advice regarding visits...

My ex stopped me seeing my son at the start of 2013 (whereas beforehand he was sleeping over twice every week) and so I applied for access through the courts.
While in court, CAFCASS recommended that we begin with supervised visits - with my ex's mother supervising the visits 3 hours a week, and hopefully after around four weeks to leave visits unsupervised.
I proclaimed how we don't get along, and that I'm certain she will do almost anything in her power to make me look bad.
CAFCASS' reply was simply that she was unwilling to use contact center's for visits as she thinks my child would feel uncomfortable.
Obviously if this was my only option then I went ahead and that's exactly where I am now.

The first week went brilliantly, however the second week was when things started getting weird.
She changed the visiting time that we'd had planned for a week, which I agreed to and went ahead with the visit (which was completely unsupervised); we done our own thing rendering these 'supervised visits' a bit pointless?).

Upon collection both my ex and her mother were there, I was informed that my son and his mother are moving to an entirely new town and an entirely new school,
I asked when the new school term started as I'd like to see him starting his new school, and this was when I saw her mother (the 'supervisor') shook her head, unaware that I could see.
I was told by my ex that i could come and it wouldn't be a problem, and that he started on the 9th of this month.
So obviously, once they had left I done some research on the school, only to find out that that school actually went back on the 5th. I kept quiet about this and thought that all I can do is keep a record of this for the court to read. I went ahead and sent a message to her saying that 'I'll keep out of the way so I don't over-complicate things', in an attempt to be civil and not cause problems.

I hoped maybe that with it being a new town and my son being a new student; that maybe he would have a different starting date to the other children. So, I called the school the day before the new term started. Gave them my son's name and was told that they would get back to me that afternoon.
However, the school had been in touch with my ex first - and so I received a call from 'the supervisor', I had her screaming and shouting through the phone. Telling me that she had lost all trust in me, that if I attended his first day then she would call the police, and basically explained that she's going to make these visits as awkward as possible for me. All of this attitude because I checked his real start date! this ended with her putting the phone down on me. I received a call back from the school shortly after - the school said that my ex would love to have me there on his first day and saw no problem with it (so obviously whatever the 'supervisor' is claiming is actually nothing to do with my son's OR my ex's interests). To keep things sweet I stayed away and just called the night before to speak to him.

Another visit went ahead for an hour, basically dropping off my son and driving away (leaving us unsupervised yet again).

Now, this morning I was expecting another meeting with my son - however I received a message saying that she was too ill to drop him off and that my ex was too busy to drop him off. I asked if she was going to add 2 hours onto the next visit and was told that it all depends on her shifts.

Obviously, as I stated to CAFCASS in the beginning, her mother is completely biased, and trying to cause trouble wherever possible.
And to be having 'Supervised Visits' left unsupervised only after one week, then obviously there is no real trust issue and this is all just a way to display that she is in control here.

What can I do to change the 'Supervisor' - that is if one is really necessary? I called CAFCASS and was told that the case had been dropped by them and to seek out my own legal advice.

Any advice at all would be HUGELY appreciated here.