Hi,
The Tot Hill chaps arrange it across several forums and social media platforms- as we are open to all Italian car marques, there is no central spot for organisation.
If you are on PH, then you can see one of the Tot Hill arrangement posts here:
PistonHeads » Gassing Station » Other Marques » Alfa Romeo, Fiat & Lancia - Saturday 3rd June Italian Car Breakfast, Southern England
I would have posted a link, but as I'm a newbie to FF, I'm not allowed!
I believe they meet at 08:45 in the McDonalds car park at the services there, departing around 09:00.
Hope that helps.
Ross