I discovered that you can down-load all the back-issues of MagPi, the official RaspberryPi magazine for free from their web-site here:

https://www.raspberrypi.org/magpi/

Lots of pretty pickies for light reading. It's aimed at education from beginner level but there are a lot of ideas and handy code in there relating to all permutations of pi from the beginning. 

I've found some useful info and ideas in there. 

Cheers.