Dom, I'm guessing you may be having a bit of trouble figuring out what winemaking terms to use. If so, don't worry about it, as you'll learn as you progress with this kit. If someone uses a term you are not familiar with, I suggest you search on it. If that doesn't help, or if you are unsure, ask questions. We'll cheerfully answer.
It looks like the volume in the pail is a lot less than 20 liters, if the pail has a total volume of 20 liters. Do you know the volume of the liquid in the pail?
Did you record the original SG or brix, from before you pitched the yeast? This helps us figure out the current ABV and guess the final ABV. The hydrometer appears to read 1.020, so fermentation is closer to ending, which is typically when the SG is 0.998 or lower. [My previous comment about a high brix must inhibiting fermentation from starting is obviously not a problem in your case, although some folks experience it.]
Do you have a 23 liter carboy? If so, proceeding from here is easy. I suggest you add 2 liters of water to the empty carboy and mark the water level with a grease pencil or masking tape. Keep doing this, adding 2 liters at a time and marking the level, until the carboy is full. Then empty the water out.
Give the wine another couple of days, then rack the wine into the carboy. Tilt the carboy at an angle so you get most of the wine out -- don't worry if during this racking you suck up some sediment. It will be eliminating in future rackings.
Compare the wine level to the markings to determine how much wine you have.
The kit is a 23 liter kit, so the juice/concentrate bag is intended to be reconstituted to 23 liters total. Typically 1 liter of volume is lost in the first racking, so the intended total after racking is probably 22 liters. You can add water to the 21 or 22 liter fill mark, which should restore the wine to the intended reconstitution level.
Insert the drilled stopper and airlock into the carboy and let it rest another 7 to 14 days for fermentation to complete.