I've noticed the same. We run a business from home and would have normally have heaps of mail every day - a mixture of private, business and junk. Since the "takeover" we can go days with without receiving anything at all. I've noticed specifically on Saturday or Monday, when lots of companies do a mailing on Friday afternoon, so we would expect to receive various communications on a Sat, Mon or Tues.
Also, posted my Mum's birthday cards recently - mine was posted first class, the grandchildren's posted second class a day or two earlier. They all miraculously turned up on exactly the same day, in the same delivery (and later than a first class stamp indicates). Very puzzling.
Furthermore, our nice posties appear to be disappearing at a rate of knots - the one we have at the moment is absolutely horrible. Rude and miserable. If he has something you need to sign for, he doesn't say a word, just thrusts the package in your hand, followed by the machine, no smile, nothing. He drives his van from house to house, ie, he drives all the way up the road, then delivers the post from house to house driving two feet all the way. It must take him longer to get in the van, start it up, drive to the next house, get out, deliver letters. Get back in van, start it up, drive to the next house, get out deliver letters ... and so on. Utterly bizarre.
Things are definitely going downhill with "Royal Mail", or whatever they're called nowadays.