Well, the lack of sorl-thumbnail came back to bite me when I got the latest version of the Django project I've been working on. Previous releases had lulled me into a false sense of security, but then the latest update, a bit too late in the evening, I had that old error:
ImportError: No module named sorl-thumbnail
So off I went again. I had no problem downloading sorl-thumbnail but everywhere I went wanted to put it into the wrong directory. It's not in the Synaptic Package Manager, and I couldn't find a PPA. Just to make it a bit more exciting, the dependency of the project I needed it for was something like version 3.2.5. The current version is 11.0.4.
Ideally what I wanted to be able to do was set some kind of flag on the install that told it to install somewhere else. Surelly there is a way to do that? But I couldn't find it. I had got as far as actually (again!) RTFM, and was browsing through the Core Distutils functionality page when lo and behold, I stumbled upon this. Not directly relevant you might think – but wait, item 13? What's this?
Yes, to cut a long story short, I had discovered symlinks. New to me, old to everyone else. It was short work to set one up, helped by this, and lo and behold: it works.
Kind of begs the question as to why I didn't do that in the first place for all the packages... but never mind. Onwards and upwards!