An informal letter asking for a favour

Hi Jen,
I'm writing this letter because I really need your help. You're the only person who knows me well enough to give me a reference for a course I want to do.
I saw an advert in a paper recently offering a free journalism course to successful applicants. I sent in an article I wrote for the student newspaper, you know, the one about legalising drugs? Anyway, they really liked it, but as there are only five places they want a reference as well. I haven't given them your name yet, as I expect this would be the first reference you've been asked to give. Is it OK if I send them your phone number? I think they want to phone so they can have a proper conversation with you and really check me out.
I know it's been a while but if you could do it it'd really help me out. I've got a new phone number, 09957 234 563, so you can get me on that, and my address is still the same.
Hope to hear from you soon.
Regards
Patrick