They are extremely disorganised at the lower levels (case officer, transport dept, etc). Paperwork goes out at the last minute, statements are cut-and-paste of woolly nonsense, letters are sent to the wrong people etc. etc. You need to stay on their case and if necessary change case officer or escalate.
They are absolutely broke. Surrey is an affluent borough on paper but in practice has a huge elderly population who cost the NHS and SS vast amounts, but always vote Tory so there's never enough money to pay for the services they use. So how you do with them depends entirely on whether they think it's financially worth fighting you; if your needs are modest, or if your needs are incontestable, they are not so bad. But if they think they can save £2.50 by dragging you to hell and back, they will cheerfully do so.
Google the Ofsted JAR (joint area review) and see what it says about provision for disabled kids. Woeful across the board, and I think says a fair bit about the lack of joined up thinking between services: if you are hoping for SALT input or after-school support or whatever then LA cba to drag in the other services and the other services take advantage of this attitude.
PWP is better than some - based out of a school, not LA buildings so has some independence.
Agree re: sos!sen. Also get on the NASSB email list if you aren't already - the Surrey branch of NAS is very active and a mine of local information, much of which is valid whatever the condition.