I suppose because their relationship is so well-established, and because Audrey having been a young mother is key to her character, it doesn’t stand out in the same way. If they came into the show now I’d probably think “No way is she old enough to be her mother”.
Linda’s and Izzy’s relationship just doesn’t make sense. As another post said, it felt like there was a big gap between Izzy and Katie, yet from the way they talk, it’s barely a few years.
It is also bonkers that there are only a few years between Nick and Sarah. He looks decades older.
Ben Price is nine years older than his character. I noticed they didn’t mention it on screen when Nick turned 40 a few years back - I think we’d have all choked on our tea!