Moto laid on the floor - Starting issues

[Fazerider]

Unfazed, when you say "Loosen the screws a few turns to let all the fuel drain out", where is the fuel going to come out???

On the image Unfazed posted, he's labelled the drain holes for you!
I like to push a length of tubing onto each spigot in turn and drain the float bowls into a jam jar. It makes it easier to see what come out and if the fuel looks clean it can be tipped back into the tank.

Also, I did try to start the bike without the choke, and it did start first time eventually but I still need to put the choke on afterwards to maintain the engine on, at least for a few minutes. Do you think it's normal ?

No. Unless you live somewhere cold. It sounds as if the bike is running a bit leaner than it should be. Possibly it's a blocked jet, but check the idle setting, pilot screw positions, carb balance and TPS setting.

I have noticed this "tick tick tick" sound when starting, so it shouldn't be?

If it's a while since the bike was last used, the float bowls will have lost some fuel through evaporation and the fuel pump will tick away for a few seconds. When they're full the pump detects the increase in back pressure and cuts off. There is also a timer so if the carbs are completely empty it may cut off before they fill… in which case you need to switch off and turn on  the ignition again.