Yes. I have done it on a number of occasions, both with and without the BA pilots on board. The 777 is worth waiting for if you can be patient ! Slots on the 777 are not as rare as the Airbus slots, which are like gold dust (and not available to the general unwashed masses off-the-street) ! If a 747 is available, that's not a bad substitute for a 777.

Top tip would be to book a long a session as you can afford. A short session will go incredibly quickly, particularly if you've got no prior flying experience and hence will have a lot of hand-holding ( I fortunately had prior experience so was able to get down to business).

Other than that, if you've got no prior experience, pay attention to the pre-flight briefing .... you want to maximise your time in the sim and not waste time having them to repeat stuff they already told you.

Finally, if there is stuff you know you want to experience, make a short list and have a chat with your BA pilot before you get in the sim so that he/she can plan and try to fit it in for you. One "cool" thing you should ask to do is a CAT III Autoland.... ;-)

Since you are on an "experience", you don't have navigation or communications to worry about, you only have to worry about the aviation aspect of flying. One of the main things to remember there is you need to "stay ahead of the aircraft". Given that you are not in a flight training situation, just on an "experience" event such as this if you feel you are falling behind, take advantage of the fact that you are in a simulator that is quick to reset.... and get the scenario reset and try again.... earlier rather than later... because the later you leave it, the less time you have to try again !

Oh....one more thing VolcanoMan..... if you spend your spare time on a PC flight simulator (or intend to "prepare" yourself using one).... forget it. Chalk and cheese. A PC sim will bear no resemblance.