As I said before the following won't help you in terms of what to expect from the LEA, but it might help you if you've been asked to write a letter when asking for an assesment. You've got a mediator so this might not even be helpful to you but it helped me when the school asked for my letter as I didn't have a clue as to what to write. The guidelines appear in Wolfendale's 'The parental contribution to assessment. Here goes:
EARLY YEARS
1 What was your child like as a baby
2 Were you happy about progress at the time
3 When did you first feel things were not right
4 What happened
5 Did you recieve any advice or help, from whom?
6 Were there any significant events or changes which affected your child in those early years.
WHAT IS YOUR CHILD LIKE NOW
(I've summarised this bit, as there's so much of it but you'll get the idea)
General Health - Eating, sleeping, general fitness ailments hospital?
Physical skills - Rolling, crawling walikng, jigsaws drawing, writing
Self Help - Dressing, feeding, toileting, brushing, washing
Communication - Points, gestures, eye contact, phrases, sentences, starts conversations
Playing and learning at home - Fave toys, sharing, finding out about things
Relationships - with parents brothers sisters. friends, adults, Is your child a loner
Behaviour at home - co-operates, shares listens, helps in house, fits in with routine, rules. Moods
Activities outside home - Playgroups, dealing with seperation
At school - Relationship with teachers, children playing reading, have you been asked to help with childs learning, with what and result
Your general views
1 how do you compare your child with others of same age
2 what is your child good at
3 what does your child enjoy doing
4 what does your child worry about, is your child aware of his difficulties
5 is there any information you would like to give, such as advice and reports from other people
6 what do you think your child SEN's are
7 how do you think these can be best provided for
8 with whom would you like more contact
9 what do you think of your family's needs and your needs?
Sorry if loads of mistakes but trying to rush it before picking ds up from school