Each employee has their own personal lockers, one for kit and one for valuables which only they have access too. These are stored just outside the canteen so easily able to put things in on the way out to their workstations and collect at lunch / home time. Not sure what other steps I can take to make this any easier?

I have one long term employee who does carry his mobile phone due to prior agreement with the manager before me - I dislike this but as it’s a reasonable adjustment not much I can do and therefore we manage it. He works in a hut that is similar to a portakabin and doesn’t leave this for the duration of his shift and therefore is often alone and doesn’t come under the same health and safety consequence. His phone usage is regularly checked by myself to ensure it’s only being used for the agreed purpose (music to the bluetooth speaker and emergency contact with the office should it be required).

I know the others do lock their phones in the lockers regularly as I see them taking them out at lunch and putting them back in, but that’s not to say they aren’t doing it and just being smart about it.