We only have 5 full days in Hammamet at the ML Manar [Mon through Fri] unless I convince myself to fork out the £300 to extend it by 1 day....
(2 adults 2 kids aged 8/5)

Anyway [obviously all this is subject to what excursions are bookable locally] my tentative plans are(days of week just as example):

Monday: chill all day at resort
Tues: 1/2 day visit to the Hammamet Medina in the afternoon (taxi there I assume); is it worth also visiting the Yasmine Hammamet Medina?
Wed: arrange a taxi to go to Frigua Park in the morning; I assume we would need a 1/2 day for this?
Thurs: day trip to Khairoun to see Great Mosque (what else to see here and/or what else could I incorporate into this day trip?) What about El Jem?
Fri: Trip to the Nabeul Market and then final 1/2 day of chilling at the Resort before leaving for the 4am flight.....

If I DID add an extra day what "must see" would you add to the itinerary (?Carthage/Sidi Bou Said - seems a long way to go jus to see a little village otherwise!) or what would you change above?

Thanks for your help [and in anticipation, specifically thanks to you Aslemma!] in helping me make this a great trip