I don't know anything about classical guitar.
For that you probably don't need to be in Granada.
If you want to have a go at some Flamenco guitar which is much more rough and ready than classical guitar
then I know someone who is very good and speaks English well.
(at least he used to speak English well when I last spoke to him a few years ago)
His name is Andre.
His web site his herehttp://andiguitar.com/en/index.html
By the way:
If you want to spend a lot of money on a classical guitar
There is a Canadian guitarmaker of high repute in Granada
More info here.http://johnguitar.com/