download is missing from some data sources (why?)

[jacksegal]

• think it might be semi technical (to do with the way we are downloading / exporting)
• if not, lets add (or maybe remove the places? feel like consistency is key? or maybe just explain which ones can't be downloaded?)

[c6andy]

think it might be semi technical (to do with the way we are downloading / exporting)

I suspect this is right. There’s an (unused) route for downloading all charities, that 500s:
https://campaign-lab-constituency-explorer.c6digital.dev/exports/constituency-charities

Similar to #41, I think this is related to Laravel Excel using a lot of memory. I’d suggest swapping it out for Spatie\SimpleExcelWriter. I’ve tried rewriting the charities exporter using that, and it works fine locally.

I’ve made a new ticket for the refactoring work (#50) which I think is a prerequisite for this ticket.