To gain access to the Turkish Bath and Swimming Pool you would have to used the main first-class stairway to F-deck. For the Squash Court there was a separate stairway to this appartment from D-deck.
The stairs that led to the squash court was located forward of the main grand staircase on
D-deck in the middle section just starboard of the bathrooms.
Not quite correct. After you got down to E-deck you still had to use another flight to get to the Squash Court. I refer you to what I posted in answer to Stefan's question: How did one get to the Squash court?
If you look at the plans on this web-site; go to E-deck. You will see the stairs which Jason mentions as coming down from D-deck inboard from E-5 with the stairs down to F-deck, near E-201. From there look at F-deck and at the after starboard-side of the Squash Court you will see the stairs that come down from E-deck. Running along the after wall you will see the passage containing the Viewing Window and the stairs leading down to G-deck; on which deck you will see those stairs coming down and the area where the door into the Squash Court is located.