sadminster, can I ask, did you go ahead with SR as coonsultant?
If so, that's who I use, and he is really helpful. When he first arrived at our house, dd1 was in full tantrum mode (wanted me to read a story again, I didn't want to!) so he got to see her best side straight away
after that, we just sat and had a chat abuot stuff - I'd filled in some forms for him ahead of time, and sent on multiple reports that filled out dd1's skills/lack of skills, so he had a bit of an idea about her backgorund.
we had also spoken at lentgh as to dd1's issues on the phone.
the way we handled it was to let him take the lead in describing programmes etc - he is the expert after all! so he came in, sat down and had a cup of tea while chatting to us, and at the same time he started trying to engage dd1 in something (anything really - he picked up a rattle of dd2's that was lying arouind that dd1 had never even glanced at before!) and he took it form there.
we had a few specific aims in mind (less tantrums please, and how to handle dd1's echolalia) - our main aim at that point was a smoother running of day-to-day life, rather than any specific learning targets (this has changed over timee - each time he comes down we re-evaluate what we are doing/where we are going)
I twend ot shy away form asking what improvement over wha timescale - it isn't really a question that can be answered by anyone with any accuracy.
good luck with the meeitng - I hope it goes well for you.