Hi Kathleen.
In answer to your question. There is a super market near to the Elizabeth Studios that is open late. I think it is called Nimfes? Anyway if you walk down the lane from Elizabeth Studios and instead of turning right at the end to go to the beach you carry straight on past the trees etc. You will come to Theodoros Appts on the left and if you go over the little bridge the supermarket is just on the right. It is quite small but fine for necessities! It is usually open til about 11 pm.