I wouldn't be surprised if an elevation plan exists, but with the breakup of the Harland & Wolff archives, it's probably in private hands. I hope I'm wrong, but I suspect you'll have a devil of a time finding it.
I remember going on the net back in the mid-90's, and looking up H&W's web site. They had all sorts of Olympic's plans on offer. I specifically remember being interested by the plans which gave the layout of the grand staircase foyers, including floor tile drawings. Not only was I young then, but the prices asked by H&W then, and now are a wee bit on the unaffordable side for the average person.
Needless to say that no such plans are any longer on offer. I remember seeing listings for other interior plans, but I specifically remember the grand staircase ones.