I think with the notice period given of a month is an ample amount of time for the tenant to prepare the necessary arrangement. If you have work or are just unable to be present on that particular service date, then it should be your responsibility to arrange an alternative. You could have a family member or a friend open the door for you instead of being charged another call out fee. Or discuss an alternative with the owner like have him/her come down to your flat on that particular date as a favour or a mutual agreement.