in cases where damange to an insured item can be repaired-the insurers shall pay expenses necessarily incurred to restore the damaged item to its former state of servlceablllty plus the cost of dismantling and re-erection incurred for the purpose of effecting the repairs as well as ordinary freigth to and from a repairsshop,customs duties and dues,if any , to the extent such expenses have been included in the sum insured,if the repairs are executed at a workshop owned by the insured,the