New job and mat leave

Hi, looking for some advice. Had my baby boy in May and I'm getting 12 months mat leave plus 3 months of accrued annual leave, so i would be going back in August 2025. I wanted the longest amount of time with baby before going back to work (3 months of it is unpaid) and also I need to do the 3 months after mat leave so I can get mat pay. Ive had so far, 4 months of the 15 months off on mat leave. A job of my dreams has recently been advertised and these don't come very often. I applied on a whim and have been called to interview. Not sure how many rounds there will be, most likely another one. If, somehow, I'm successful (say they offer the role in October), I'll have 9 months of mat leave remaining. How likely is it that the new company will give me this job for 9 months later? Do i have to tell them I'm on mat leave? Will it help the situation by telling them and if so when is the best time to tell them? Any advice on what to do would be great TIA