Hi this.to.firstName,

I hope that everything is going well for you and the team at company.name. I miss what.I.miss!

At the moment, I'm applying for work and I'm wondering if you would be happy for me to list you as a reference in my applications. If so, can you please provide me with the best phone number and email for any hiring managers to contact you?

I'll be in touch again to let you know if any applications reach that stage, but in the meantime please let me know if you have any questions.

Thanks in advance,
this.fullName