Your question is too general and misleading.
Lessons learnt?
By whom?
In whose opinion.
Break it down into separate enquiries.
How much money spent from x-x by LEA on services?
What depts. for
And so on.
They will never give you more than you aks for.
Irrespective of your own personal issues with them, it is not unreasonable for public sector bodies to emply legal experts to exempt them from claims by unscrupulous folk.
I could tell you some hair raising tales of people trying it on to get their hands on tax payers' cash.