Sarah, I work in HR, and although your company's holiday policy may be that you have to use it or loose it, while you are on mat leave, legally you have to accrue benefits as you would whilst in work and so you have to still get your hols and if you can't use them then you should be allowed to roll them over.
This article explains a little more https://m.acas.org.uk/index.aspx?articleid=4289
Just wanted to let you know as more often than not I know women I have dealt with maternity leave for have left a few weeks before baby is due, preferring to maybe roll some hols over to tag onto the end of paid mat leave so they have more time with baby.
It should all be your decision as to when you start your leave etc, obviously working with your manager to set a date is the courteous thing to do, but if you're not wanting to finish in November, you shouldn't have to as legally you should be able to carry hols over.
I'm ok Jessy, but full of cold and it's been 2 weeks now. I think I've had one and then just as its easing off I've caught another! I feel so run down and tired and hubby is working today which stinks as I could really do with him being here!
So hard to decide on the section, are you due any more scans to see how big baby is looking before deciding?