A ballot is counted if it's clear on it who the voter intended to vote for, doesn't have to be an X or a check mark or anything else in particular, you can put an asterisk or write OK or YES or whatever you want in the little circle by the candidate's name, including filling it in with a pen or pencil. As long as only one candidate is indicated, and there are no marks on it that could identify the voter, it's a valid ballot. Otherwise it's rejected as not valid. I've been a scrutineer at a polling station and I'll be doing it again tonight, scrutinizing the count, and those are the rules I was given when I took the oath this morning. .
And BTW, regarding the OP I think Nick has it right.
And BTW, regarding the OP I think Nick has it right.