The missing piece

The jigsaw company has sent me a whole new puzzle to replace the one with the missing piece!! Do I do the whole puzzle again or try and find the one piece just to prove we finished it???
It’s on the spare bed atm ( luckily no one’s coming to stay) but we go away in a couple of weeks and I’d quite like to start laying stuff out.
Apart from that a quiet admin day except the internet went down for a few hours as they were digging up the road so I had to use my phone as a hot spot. R couldn’t so got huffy!
I’m just about to do my 100 skips before I go to martial arts while it’s still light.