Okay, I am going to try as best as I can to give you the facts and hope that my tone isn't too harsh on this one.
I flew with DD(7) in April with Virgin from Manchester. I booked GF meal with our original booking and phoned in to confirm a week before departure. It didn't say anything on the tickets so I panicked (you will understand this) and called again. They assured me my request had been noted.
When the food came around on the flight I was surpised when they came and asked what she wanted. The short story, there was no GF meal loaded on the flght. I had to explain that there was no way I could take a chance. The last thing we needed was an allergic reaction to start our stay at Disney ....! They were very nice and brought her fruit and yogurt but the poor child had been up for seven hours before we took off (we had to fly down from Edinburgh to get our Virgin flight) and fruit and yogurt hardly stave off hunger pangs. About three hours into the flights both of us were in tears. I felt guilty about eating a meal when she wasn't getting anything.
We did contact them in Orlando and they noted it for the return flight and guess what .....same thing happened. But this time I had packed some extra things in my hand luggage. Again, I can't say enough for the flight crew. To say our stewardess went out of her way is an understatement.
Don't get me wrong, I love Virgin and we are using them again on our next trip. Also, they responded immediately to my email on my return and I had someone personally dealing with my complaint and she was constantly in touch with me so it was really personal service. They also sent my daugher a £20 voucher and a card apologising to her personally. I think this is extreme fluke and unlikely to happen again, but to be on the safe side, rather pack some stuff that you can take through security just in case. I would imagine, like me, that you take a good stash of dietry special dry stock in the hold luggage anyway (I did, but could't reach it there..... silly me).
In regards to the GF meal itself, some of my family members have had it and said it is really good food. They are of the view that their meals looked better than those of the other passengers. So please don't take this as a criticism of the airline - it is more of a caution to just do as you probably usually do and have some back up stock.
Next time I am taking a couple of GF sandwiches. If they don't get eaten I think you have to leave them on the plane as you can't take meat, cheese, etc into the US, but I am happy to part with them if need be, just for the sake of peace of mind.
You don't say when you leave. I am keen to hear how it goes.