In the following image can anyone tell me if the marcato is for all notes in the first bar or 3 bars, or for the duration of the complete score.

Without seeing the whole score, no, not categorically. I’d hazard a guess that it’s for those three bars, or until the next dynamic. If the next entry is only a few bars further along and contains similar material but no new dynamic, that’s probably also marcato.

Thanks, There is a new dynamic 5 bars later so I’ll use it for the three bars.

IF that’s just a dynamic suffix text, it won’t actually be marcato.