water has grounded it out
hold the key and have someone "tap" the starter with a hammer,easy taps...
the mini has a round washer disc/plunger rod for a contact and the will get pitted some and do the "clicking" thing
if it loaded with water inside the starter it might have short the contact,the tapping might get it to move..
make sure no water is on the terms of the starter relay ...does it hit by jumping the relay?
I have had a few stock min starters do the clicking and a quike rebuild and a start shop takes car of it
will use same contacs as a yota starter also
my local alt/starter rebuilder got the kit and installs it 65$
might try napa for it also
but then again,if it drys out and works you may be ok
good luck