You need to go into town to change sterling to euros. There is a possiblility that some shops may change for you but I would think it would be better to assume that they don't and have enough euros to tide you through until you go into town. If you are staying at a hotel it would be worth emailing them to see if they exchange. However, bare in mind that hotels are not great usually with exchange rates.
It would be handy if someone out there now could give us the exchange rate they are getting as it could just be the case that it might just be easier for you to buy your euros in the UK

Thanks for the quick reply. I will take enough to get us going. Last year in argassi we could walk in to any supermarket and get some and in koukounaries our hotel did it at a better rate than at home

that's why its so difficult to know how much to exchange before you go isn't it? Hotels can give a poor rate compared to other places but they may well still be better than in the UK.

In every Greek island I have stayed there have been plenty of places to change money. Usually the best places are the car rentals.

Thanks qman. We have never had any problems either but i read somewhere that Troulos doesnt have much in the way of exchange places. In my experience every hotel we we have stayed in has been able to change
sterling but we are staying in much smaller studios this year.