Hi Tim...sure you'll love Symi and, if you go end of May/September, you're bound to bump into a few of the site regulars. Whether you consider that to be an incentive or not depends on your point of view
Looks as if you will have to take a Wednesday flight from Newcastle but, as so many UK flights are on a Wednesday that won't cause a problem at the Symi end. We book on line through Travel Republic
http://www.travelrepublic.co.uk and have always found that they offer all available flights and are very efficient. They are ABTA members which I find reassuring too.
Best of luck with your arrangements.