A great bargain break to Menorca in the Easter holidays as well, under £130pp!!
This trip leaves on the evening of 31st March and I believe most schools break up on this date (I checked a few schools in the Midlands area). Flights are with Ryanair so only includes hand luggage but this should be easily achieved for a week.
The accommodation is the California in Cala en Blanes and has good reviews on Tripadvisor and has a pool too.
I've included car hire, this isn't the cheapest but is a better car (4 door) as oppose to a hatch back. This is only basic cover so you'll want to take extra insurance out which you can do at places like insurance4carhire if you wish.
Flights with Ryanair £249.92
Accommodation book at Amoma.com using code AMO0201 (the code is on their Facebook page) £239.40
Car Hire book via holidaycars.com £23.64
Total price £512.96/£128.24pp