I suppose you realise that if you send an express post item and it doesn't arrive the following working day, provided that both the sender and recipient reside within the specified express post network as published on AP's website, the sender will be refunded the entire cost of postage applicable?

I'm not suggesting that express post is 100% foolproof but I use that service at least 100 times a year and I can count on the fingers on one hand the number of times my package hasn't been delivered by 5pm the following working day and on each of those occasions I've received a full refund of the amount of postage paid.