Hi Des
You could put a line of capillary matting on your staging with both ends hanging in a trough of water (make sure the whole of the matting is soaked). The matting stays wet, the pots stay on the matting and draw up the moisture from the matting. Always good to have a friendly neighbour to check that there's enough water and nothing's getting fried in the sun. I've also got the Gravity bag/drip system for my grow bags - it's a fantastic bargain and provides a stress-free holiday!
Good luck!
Nathalie