The value in @@DATADIR is wrong it doesn't match the value in my.ini

[Linda Petty]

On Windows
I've upgraded mysql to 5.6 (from 5.5)

I have a database called confluence which I need to upgrade
here's the location of my datadir is in my.ini

datadir="C:/MySQLdata/Data/"

however when I check the value of @@DATADIR in mysql with

select @@DATADIR;

I get something entirely different:-

C:\ProgramData\MySQL\MySQL Server 5.6\DATA\

so mysql is looking in the wrong place

What's the syntax for updating @@DATADIR via SQL ??
(I tried) is it back slashes or forward slashes? double or single?

Any ideas why Mysql 5.6 isn't using the datadir value in the my.ini file ?

With other versions of MySQL my.ini is found and used OK. (eg with v5.1 & v5.5)