I gather from your e-mail that your intension is to stay where you live if your daughter does not get a place at one of the above schools and your daughter can therefore go to the excellent school which is local to you, or move if your daughter does gain a place. If I am wrong on this, and you are moving into Essex anyway, please let me know and I will recommend what, in my opinion, are the best state comprehensives.
Yes, the 4000 is for all Essex Grammar Schools and those schools in Southend on Sea which have a grammar school stream. However, as you say, the ratio for passing into Chelmsford or Colchester is 1-6/1-7 and, yes, it is scary.
I do not think your daughter will have any difficulty making new friends at one of these schools because, certainly as far as Chelmsford is concerned, there are quite a variety of different personalities. As I said previously, there are a significant number of ex prep school girls there and I am told they can be quite snooty but I think that once they are all in the same uniform and in the same situation things chance.
There is a school of thought which says that grammar schools are the bastion of the middle and upper classes and I think this is true. Therefore, what you will definitely find at any grammar school is that a large number of pupils have parents with money. When I say money I am talking about big bucks as opposed to being comfortably off. However, there are always a few "have nots" so whichever category you are in, there is no reason why your daughter should feel left out from the crowd.
In my experience, the grammar schools are challenging but not encouraging. They tend to expect children to encourage themselves. There is very little in the way of prizes or awards, etc, for those who score less than A*s in all subjects but if it is challenge your daughter requires then they are undoubtedly the most suitable schools.
One thing to remember is that schools are only as good as their intake. T the results in the league tables of both Chelmsford and Colchester are highly impressive but as they cream off the very best 11+ candidates, then you should expect no other results.
For the sake of good measure, I will tell you that I think the best grammar school of all the Essex grammars is Southend High School for Girls. SHSG as it is fondly known is a very friendly school, where, whilst girls are challenged, they are allowed to be "who they are".
You probably know that neither Chelmsford or Colchester have a catchment area and so you have as much chance of getting in if you live in Chelmsford/Colchester or Edinburgh. SHSG does have a catchment areas (as does Westcliff High School for Girls, also in Southend). They both offer 150 places annually and 115 of these, at each school, is reserved for "in catchment students" who sit and pass the 11+. The remaining places are then offered to students from anywhere outside the catchment area who has requested a place at the school, according to the "order of merit" on the 11+. (This means that you still have a chance of a place at these schools, no matter where you put them on your list of choices).
There is very little difference when all is said and done between the levels of performance at Chelmsford/Colchester and the levels of performance at Southend (or Westcliff for that matter). When you realise how small the difference is, and you take into account the fact that Chelmsford/Colchester take from the top 500 or so and that the Southend schools take from around the top 900 outside catchment and 1500 inside catchment (approximate figures only) you have to agree that the quality of teaching, etc, at the Southend schools must be excellent.
One more thing to say about Southend High is that the headship has recently been taken over by an ex deputy head of KEGS (Chelmsford boys grammar) and he is making very challenging changes to the curriculum. The new year 7 intake study both French and German (and a small amount of Latin) and will all be studying for three separate sciences at GCSE (as opposed to the double science award). SHSG is a language college and studying one language to GCSE is therefore still compulsary.
Again, any further questions, feel free to ask.