How to Get Lots Of British Passport?

So we have 3 days to unlock the first Chapter on Challenge Mission : London - Steal A Crown Jewel..

Meanwhile you can use the remaining days to collect as many passports as you can!

British Passports

To complete the jobs in London, you'll need to use special British Passports. Each day, you'll be able to collect these items from the Challenge Mission page, obtain them from the Marketplace, and find them from doing jobs, fighting, and robbing in other cities. Make sure you save them up as you'll need more as the mission progresses!

How to get the British Passport?

1. Go travel to London and collect your passports every 24 hours. You will have a chance to collect 12 passports.
   
2. British Passports can drop from any job, fighting and robbing.
3. Fill up your crew to help you in London! You can gain British Passports as a one time bonus by adding more mafia members. (See my explanation about this on previous post)
   

This is the example when you get the passport from clearing the whole grid on Robbing.

And this one you get from doing any job..

Still having unclear info about "My Crew" feature as you can add 7 mafias right away but don't know when the to get the bonus of British Passport for each mafia members added..

PS : Thanks to [G]-Bull, Graciano, Arbid and Micah!