Hypothetical question - in order to earn £15-20k pa as a writer what would my working life look like? Totally not dreaming of giving up the day job 
Self/traditional publishing? How many books/how often?
Teaching/other bits and pieces - if so, what would they be?
Anything else as a lucrative income stream?
I don't write for the money (fortunately!) and am aware of the dire earnings of writers and so on... but wonder what it would take to be able to write full time. I know it's a bit of a 'how long is a piece of string' question!