Visa refusal overturned.

Hello all,

Today I got an email from the UK govt stating my visitor visa refusal has been overturned, and that I should submit my passport within 15 days.

I am happy with this but does anyone have any idea how long will it take for my passport to get back to me? I have to submit to VFS and I think they are quick but I'm not sure as I have to travel in the coming months.