10 and 12? Sure, why not? Just keep in mind that it's a LONG meal, and make sure they are aware of this and ready for it...it would be an expensive mistake otherwise.
Other points to ponder...no kids menu, and no half price for kids--regardless of age, you pay the full price. Also the food is very gourmet, and the menu is limited and changes daily, so you can't really plan ahead. IF theya ren't really adventurous you might want to think twice about it.
If you decide it's not a good option at this point, there is childcare at the Polynesian that they would enjoy. The childcare at teh GF is really geared towards the younger crowd. We left DS there while we dined at V&A's (he was 10 at the time) and he was very bored.
Anne