Thanks Con!
I did have a look at other pictures of wood mites, they look very familiar, only thing is that they did not grow much bigger than a teeeeeeny tiiiiny grain of sugar, and they're white as white can be.
They're gone now, and i'll stay away from bark and other 'woody' substances, i'm upgrading to a bigger tank today with more ventilation so hopefully this will help too.
Whew! Thanks!
On a lighter note, I caught my two BP's having a 'moment' this morning!! Eeeee!!