She would override it. Having said that, the SEN CoP isn't terribly clear. It says that they have to take your preference unless there is good reason not to, but one of those reasons is 'incompatible with the efficient education of other children at the school'.
If your DD is going to be Year R, her admission will fall in the Infant Class-size Regulations, prohibiting more than 30 children in a KS1 class.
Technically, if the LA admit her to your chosen school after the 30 places per class are allocated, she will be classed as an 'excepted pupil' for that year. i.e. she will be allowed to be pupil 31 until Year 1 without another teacher. But in Year 1, they would need to make sure that they kept to Regs, and that could mean employing another teacher, or splitting year groups into Year R/1 mix, etc.
All schools HAVE to admit any statemented child where the school is named in Part 4 of the statement, which leads people to think that they are home and dry, but they sometimes forget that it is the LA who have the final say on which school is named in Part 4.
What you would need to do is express a preference for that school in each and every document you send, even the initial letter requesting SA, so that you are flagging your DD. Hopefully, they would then count your DD in the numbers, although it does get tricky with application cycles and deadlines.
Regardless, you will have the right to appeal to the First Tier Tribunal (Special Educational Needs and Disability) [formerly SENDIST] if they name a school which is different to your preference, but then you'd have to show that your DD's needs override the Infant Class Size Regulations which is very hard to do.
The other approach is a standard appeal against the school place, but again, to win you would have to show that the LA was grossly irrational in its decision making.