Garuda First Class offers one of the best experience and it's in my Top 3 First Class product out there.
To book you can click on the link below:
Google flight will display a wrong price. Click on expedia buttom to book it at the right price. 2380£ / 2650€ / $3100
Yes, it's a lot of money but it's the cheapest deal from London to Singapore in First Class.
For more info about the product : https://www.garuda-indonesia.com/id/en/garuda-indonesia-experience/first-class/index.page
You can collect 25,000 miles with Flying Blue while Delta will award you 21,000 miles.
To collect the most, you need to cedit your flights with Chinese carriers or Aeromexico where you will collect over 34,500 miles.
Enjoy Garuda !