water seeping through garage wall

[dal]

looks like a cap of cement at an angle to let the rain run away ..
if it's your neighbour's shed .. will he let you put a gutter on and where would the water run to ?

Yes neighbour's said yes to gutter but i think I'll have to dig down further at the far end to allow the water to run away, will probably put some cement down as well to help rain run away.