Our tours brochure arrived too late (and from Chicago ???) for us to book in advance, so we did so on the ship. But I am pretty certain that you can book your tours on the Cunard website. I thought it was under the 'cruise personalizer' section, but of course as we don't have a future booking :-( can no longer access that part.
If you can't find anywhere on the site, then maybe drop a line to Cunard, or check with your travel agent.
Hope that was of some help,
Alan & Katrina
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