Voluntary work whilst off with children always looks good. Don't worry about not having done fundraising before. It's really not rocket science. Same skills as you'll have covered elsewhere if you've got a marketing background. Will you be working on public appeals? Like getting individuals to give cash out of their own pockets? Or is it businesses?
I would guess some grants (?) as it has definite links with NHS and mentions help to secure funding. Otherwise the limited examples I can find relate to dosh from public. Cannot see any reasons not to tap business though - except possibly British Tobacco
If the job desription doesn't say, it could be various sources, which is a good way to start in fundraising. Work on grants is often about research and good writing skills, if you ask me, and donations from the public is all the usual marketing stuff and events.