What is ' chicken garlic chicken '
Purely conjecture but...

You've heard of chicken fried steak... right?
We also have chicken fried chicken... which is chicken prepared in the same way as chicken fried steak. It's different than "fried chicken " because it's a boneless (often pounded) piece of breast meat. 

It's amusingly recursive. 

So, based on the description on the menu, it sounds like a version of chicken fried chicken but with lots of garlic, so maybe they decided to replace the "scary" word, "fried" with the delicious word "garlic". 

Unfortunately this conjecture falls apart somewhat since chicken fried chicken is a staple of the southern US and the menu seems to be from a pub in England somewhere.