Office based job. Legal requirement to start mat leave by 38 weeks.
In my case, the rest of the office flew to go to an international conference (in Hong Kong, I cried having to cancel my seat on the plane!), on Friday 9th December and we were pushing up to COB on Thursday to finish all the briefing and other materials for it.
I finished clearing my desk in peace and quiet on the Friday, and then left slightly early (to make up for working late all that week).
DD's EDD had moved around, from 25th initially to 23rd by departure.
I spent the first week going to medical appointments and my last PG yoga class, I got 1 swim in, and writing Christmas cards (nothing done for Christmas at that point). And the following week buying and wrapping presents, doing laundry, and generally prepping for Christmas. And slowed down ever so slightly.
Spent Christmas Day running around between family, and DD started making her appearance that night (arrived at 6am Boxing Day).
At the time, mat leave was only 14 weeks and I was charging around the place (and GP on shared care was happy to sign me off sick if I needed it earlier) so I didn't want to waste those few weeks if I didn't need to. (I took a month unpaid after as well, before going back when DD was 4.5 months old).