Going to versus Going to go

There seems to be a difference of opinion in the textbooks in the use of "going to" and "going to go". The Headway book teaches the student not to use "going to go" only "going to". BUT in the English File book it clearly shows the student using the form "going to go". So, i did a bit of research and found some information. Although it doesn't say it is completely wrong it does say "it is not common to say "going to go to. We normally drop the go to and just say going to."

http://www.britishcouncil.org/learnenglish-central-grammar-future-forms.htm

I did find this interesting quote from an ESL teacher which makes a lot of sense.

"There is nothing wrong with the grammar of going to go. It's just that it sounds repetitious, and the to go in going to go can be omitted to make it sound nicer. The present continuous is going has a future time meaning anyway, so the additional use of the idiom going to to indicate the future is really unnecessary."