Hi Claire.
I registered for a course last month, and I too have entitlement to financial help. The process for me happened very quickly (though I was already registered with the OU for a previous course, so this may have something to do with it), I printed all the forms from the website (including the form for financial assistance), completed them and posted them. Within a week I received confirmation.
You could phone them. I'm fairly confident that if there's been a hold up they'll probably extend the closing date for you.
Alternatively, you could register for the January one instead, and do a 10-point Openings course in the meantime, which are very easy going and designed for people who are new to the OU.
I hope I've helped.