As per the subject, searching for "new blood" (either on the command line or --pvr) only returns the first episode, while 3 are available.
Using the pid I can download them.
get_iplayer 2.94 (I didn't spot any relevant change on github since then).
Something similar happened with the hollow crown.
Look at the broadcast dates before posting this sort of question. None of those shows has been broadcast. Part 1 is in this week's BBC One schedule, so is picked up by get_iplayer during indexing. Part 2 doesn't appear until next week's schedule, so get_iplayer won't pick it up for indexing until then. Part 3 presumably won't be available until the following week. For programmes made available on iPlayer before the week of broadcast - and thus before they will be indexed by get_iplayer - use --pid.
Yes, that is confusing. "First shown" in this case refers to the date made available on the iPlayer site. You have to drill into the programme website to get the full story. This will be happening more often in the future, I suspect.