What is the difference between F5AL250V and F5L250V fuses?
They are the same 5A 250V fast acting low breaking capacity fuses (just one omits the A of ampere)

The glass cartridge fuse code is structured in this way 

|Acting Speed| |Current rating| |Breaking capacity| |Voltage rating|


or 

|Package size code| |Acting Speed| |Current rating| |Breaking capacity| |Voltage rating|


Acting speed

The time it takes for the fuse to open when a fault current occurs. 
It code could be:

FF - Very Fast Acting (Flink Flink)

F - Fast Acting (Flink)

M - Medium Acting (Mitteltrage)

T - Slow Acting (Trage)

TT - Very Slow Acting (Trage Trage)

Fuse Breaking Capacity

It is the current that a fuse is able to interrupt without being destroyed or causing an electric arc with unacceptable duration. The capacity of a fuse to operate between the lowest and the Rated Breaking Current code could be:

H - High Breaking Capacity

L - Low Breaking Capacity