3.13 fails to find "Strawberry Fields"
Using the Windows 10 CLI, I ran
get_iplayer "Strawberry Fields"
but it didn't find any matches.

However, I could download the programme using the PID:
get_iplayer --pid b037nqvz

This suggests to me that version 3.13 may need some further tweaking.
Don't think so. I just ran
get_iplayer "Strawberry Fields"
and got :
get_iplayer 3.13.0, Copyright (C) 2008-2010 Phil Lewis
 This program comes with ABSOLUTELY NO WARRANTY; for details use --warranty.
 This is free software, and you are welcome to redistribute it under certain
 conditions; use --conditions for details.

6285:   Strawberry Fields - -, BBC Two, b037nqvz
INFO: 1 matching programmes

Sounds like you didn't refresh your cache.