SFP ( seller fulfilled prime) not activated yet, how long does it take?

Hi,

I’m hoping someone can help me. I’ve have been selling on Amazon for a couple of years but have recently decided to go for SFP. I applied in early January and have since sent 27 ‘prime’ shipments with 24 Tracked shipping with Royal Mail, through the buy shipping button. All orders were sent and delivered on time and our account health says it is perfect. The 25th order was despatched exactly a week ago and I would have expected our Prime Trial to have been passed by now, but it still hasn’t been. Am I missing something or do I just need to wait longer for it to be activated?

Thanks!