The only problem with Parcel 2 go etc is that your contract is with Parcel 2 go and not the carrier. This can complicate any issues.
Or if the courier decides that due to an unspecified Major Event on Friday, their next day guaranteed delivery was not valid, and I have a pissed off punter, and no comeback, as my contract was not with the courier. Cue, I'm out of pocket for the postage there, the return postage when it does turn up (as buyer needed by Saturday), and other costs, none of which I seemingly can claim back. And yes, I had paid the extra for insurance, fortunately, as my best hope is that the courier has lost it (it which point the insurance kicks in, and I can claim).
Now, had my contract been with the courier, I would easily get my out of pocket back.
Unaware of any such major events on Friday. I think a small section of the M5 was closed for less than an hour, though if any courier was sending my parcel anywhere near there, they have bigger issues.