Fing is a really handy app - Lets you see what all the different devices are, what IP they're assigned mac address, network hardware manufacter/vendor, what services they provide (FTP/HTTP/SSH/etc), and really handy when monitoring your network over time, as you can assign friendly names and attach notes.
Thanks for that thunderace... didn't even realise thats what the 6 letters after the ACORN- were! Nice!
Pete