Banks will be most interested in assessing how likely is the funding going to continue. So if the grant funding is just for the completion of a specific project, e.g. a piece of research work, then it's finite and will end when the project is completed. But if the work is more open-ended and could in theory go on for a long time, tell the bank this at application stage, providing as much proof or back-up as possible.
Also if the person has specific qualifications that would be in demand point this out also.
I know that Haven tend to look favourably on contract-workers, provided that they can be satisfied that there's a reasonable chance the person will continue to be employed for a good while.