Will echo the sentiments of everyone else. My suggestions are: Egypt, hot but cooling down from the high 90's..makes it more bearable. Gran Canaria - lovely at any time of the year and you will get good weather. Also, Tenerife will be hot too..and last but not least, Lanzarote..although the weather may be a little more unpredictable there.
Egypt is about 5 - 6 hours flying time from most UK airports and the Canary Islands can be reached in about 4 - 4.5 hours from most UK airports.