When an alternative full length runway is available then the runway being worked on should have been fully closed for the work to be carried out. If the single runway operation causes complications whether it be delays or environmental then the works should be planned at times when traffic schedules are light i.e during the quiet night hours.
LHR and LGW plan runway works in this way, however at single runway airports like STN it must be very difficult to plan runway closures for work when the demands of airlines require the runway to be available at all times. STN has just completed runway resurfacing when for 9 months and for 3 night a week the runway operated at reduced distance with many movements taking place without incident. It can be done if all involved take the time to identify the risks and how to mitigate against them.
Looks like MAN could learn a lot from LGW, LHR and STN when it comes to planning and carrying out runway works.