hi,
my 1st post-so hi guys and hope you can help

i have taken a mira shower off my mothers wall-it was disconnected by the previous owner-i.e all electrics so i just have taken it off the wall.
the thing is it is half full of water-i dont see any drain button-and as it is to be posted off to someone i obviously dont want the water to add to the postage
any help much appreciated
model is mira advanced thermostatic atl 8.5kw