For those who want to keep track of progress, I've created a spreadsheet with despatch dates and receipt dates that individuals can add dates to as the lens moves around, and modify the ordering. Of course, it's entirely voluntary, but satisfies my ambition to keep an eye on how things are going, and allows the current holder to make a better judgment about who to send onto.
The Forum only allows certain types of attachments, so I've zipped the Excel spreadsheet.
Nifty50Progress.xls.zip
I'll try to keep a master copy going.
Apologies for wrongly attributing the original list to séamuis, when it was actually jsherman999.