Thanks for that, I didn't know what they were called so couldn't google it. I was going to implement this on vero board, any tips on if that is possible, do I just need sections of the tracks either side of those pins at VCC?
Thinking about it more, obviously it won't be possible/effective to use tracks either side of pins 2 and 3 as guards,, I wonder if folding those pins out to the side and soldering to a little mezzanine board would work to isolate them from leakage?