Great news! I love the increased small parcel size. My boxes are a bit tight for the measuring box so I cut them down a bit. Last week a new lady tried to charge medium parcel as my box was too big. I pointed out that hers was dented and therefore smaller - I ended up measuring my parcel to prove it. Much to the delight if the large queue!!
No, that’s a shame as a fellow seller of things that are light-but-over-5mm, but if the parcel is less than 60g you’ll save 80p or so on the postage.