It sounds a lot but it should be very achievable as it is less than 14 movements per day. A FBO at Luton is renting spare airline stands until the end of March due to the demise of Monarch. Come April those stands which can hold several biz jet each will go back to the airport. There is still a large choice of alternative airports including Stansted, City, Farnbough, Biggin Hill, Cranfield and Oxford but only Stansted is 24 hour so Southend should do well.