I have decided to bottom feed them at this stage as it will be easier to keep the soil moist while I am away. I will use a bbq skewer to check moisture levels so that I avoid over watering this way. I will be away for a week. @Azimuth this is not unlike the SIP setups, just a little cruder. Do you think it would be safe for me to leave the pots in a couple of cm of water when I go, or would that endanger the roots?
The magic to the SIP is not bottom watering but rather the air gap which your pots don't have. So I would say, no, not safe to leave them sitting in a puddle of water while you're away.
A better alternative would be a quick and dirty swick. Here's how I'd do it:
Find a short piece of some sort of cordage that will wick water. You could use a shoelace, or thin polypropylene rope, thin slices of a cut up t-shirt, something like that. I'm not a fan of cotton for a long term set-up but it will be fine for your short period away.
Make sure whatever you choose can wick water by putting one end in a glass of water with the other end a few inches higher. You should see water make its way up gradually to the top. For the test I'd use a tall glass with water in the bottom inch or so and the top of the wick draped over the glass rim.
Once you're confident your chosen material can move water you can insert the top end up into your pot. Your call, but you could either transplant your existing plant into another pot with the wick already in place, or stuff the end up through the drain holes in the bottom up into the pot maybe an inch or so with maybe a knitting needle or BBQ skewer.
Then place the pot with its wick dangling out the bottom over a bowl of water so that the wick settles on the bottom of the bowl but with an air gap between the bottom of the pot and the water. With enough water in the bowl, your plants will keep watered for quite a while.
Then find some way to suspend the pots over the bowl of water with the wicks to the bottom of the bowl and you're dancin'. I'd probably use a couple of long handled wooden spoons to make a two railed bridge over the bowl and set the pots on them.
Do they list the ingredients? I'm guessing maybe fish or seaweed, or maybe even both!