Night Cover in Extra Care

We work in a number of extra-care schemes, some of which have waking night staff some sleep-in staff. The decision as to which has tended to be related to the model of extra-care provision selected - if the service user group is at the 'heavy' end of dependency then waking night staff are required. Waking night staff have prevented the 'loss' to residential care of tenants who have consistent and regular night time needs (difficult to accommodate with sleep-in staff for a good employer).
Other matters for consideration are: Lone working - we are fortunate that other services are provided in the buildings where we have active waking staff and there is a supportive partnership that helps with lone working issues, and we also have a manager on call 24/7 who can attend in the event of an emergency (as per National Minimum Standards).
Working time directive: can cause operational issues with rotas and attendance if sleep-in staff also work during the day . If they are heavily disturbed can they be expected to work the next morning?(also a H&S issue).
National Minimum Wage issues (Harrow ruling) reduce the difference in cost between sleep-in/waking nights, making the latter more attractive, given the enhanced service possible and widening entry criteria for potential service users.

We use assistive technology - bed sensors for those at risk of falling, and motion sensors for those likely to leave their flats - in our scheme for people with dementia, as a support for good practice, rather than a replacement for adequate staffing levels (cynic that I am).

With regard to extra-care schemes with 24 hour care provision on site - who funds this? Is any of it funded by 'supporting people' grant as a housing related support service?