Problem changing Frame rate for Delivery

I am just finishing editing a video shot in H264 4k PAL at 25 fps with a Panasonic consumer camera. First time I have tried this in Resolve Studio (17). When I go to Deliver the project I only get 23.97, 24 and 30 frames per second options available. I have set 25 fps in the Project Settings except for the Timeline Frame Rate at 24 and which I am unable to alter. I have not had this problem with BRAW files.
Anyone able to help?

Well, Murphy's Law applies again. Just when I thought I'd exhausted all possibilities, I seem to have solved the problem.
I saved the Project with a different name and created a new Timeline. Changed the setting there to 25 fps and then dragged Timeline 1 onto Timeline 2 and now I have 25 fps. File now rendering - and I think I've earned a glass of sparkling shiraz.