Would the Royal Navy donate it to some historical organization to become a museum (like what is done with several retired USN ships)? I had a limited visit of the Invincible when she stopped in New York a few years ago and I think she would make an excellent museum (and would hopefully remind the British public why they need carriers ).
From what I gather India has considered it in the past but I as the vessel wont be put up for sale until 2010 I would be surprised if they were still interested.