Good day @dannyg,
Is reinstalling from scratch an option?
This might be a problem with uninstalled dependencies, dependencies in different versions than needed or simply modifications in the internal files.
When you say
I'd say the latter is quite probable.
Reinstalling ros and it's dependencies might just be enough.
Also, before thinking about reinstalling, have you checked that you are using the whole SD's storage? I'm assuming you got a 8GB card but if that's not the case your system ain't using it's full capabilities and you'd need to resize the partitions yourself.
Here we stopped using 8GB cards (every order with an SD is either a 16 or 32 GB card) a while ago because of total storage space.