Your son has done very well - he is above the mean score in a very competitive examination. Any child who prepares for and takes this exam has achieved.
As you can see from the grammar schools page http://www.kingedwardthesixth.org/offers.htm
, your son's score is lower than any of the lowest qualifying scores for the grammar schools last year. The score for Handsworth Grammar were based on a different exam last year, so there is no comparison available. Historically the scores have risen year on year, but because there is likely to be additional forms at the KE schools in September 2014, they may possibly drop. But it is unlikely that they would drop enough for his score to admit him in CHB, Fiveways, Aston or Bishop Vesey as a ten point drop (for last year's BV score) would encompass a very large number of children.
However, Handsworth Grammar has historically been the school where those who miss out on KE schools often gain a place. So it is possible that his score of 207 may be enough for there and it would definitely be worth putting the school on your LA form. You should ensure that your form includes a good alternative school to the grammars in case your son does not gain a place.