I'm actually an international student too, and from what I've read in the UKBA policy guidance we need to show proof of funds for the first year of our degree (£19500) and for maintenance (depends on length of course but assuming full time living in London, £9000)
Where did you hear about the £10,000 thing? It would definitely be relieved if that were the case!
As for the scholarship...shouldn't home students technically not be eligible either since all can receive full sponsorship from the UK government? (maintenance and tuition covered)
I assume then that by "unable to cover the costs of studying at UCL" means general financial hardship, ie having to take a hefty loan and not being in a position to easily repay. Applicable to both home and international students.
I've phoned the office, and there's only one of the Denys Holland scholarships being awarded this year. Given the relatively generic eligibility requirements and the high value I would imagine it's massively competitive.
Still worth applying though - especially as an international student!