Chat with recuiter
Wait 3 weeks
First Interview with line manager
Wait 2-3 weeks
Second Interview with 2 group product managers
Wait 2-3 weeks
Interview with Head of Product
Wait 10 days-2 weeks
"Not this time" but we'll keep you on file
Amazingly this wasn't a lie, 2 weeks later there was another product role, for which I had another 45 minute interview
Wait 4 weeks
Offer
Ultimately everyone was very nice and competent, and Form 3 seems like a great place to work. however, in the time it took to receive an offer I received an offer from elsewhere, which I took instead, and had signed a contract.
From my impressions of Form3 it seems like a very good place to work, but nearly 4 months from initial first chat to offer is a very long time (with all the caveats that I know how busy everyone is)