If you hold shares in an ISA (which currently has to be a nominee account) then only your stockbroker can give you a vote). But many do not, so change to one who does. Glad to see the Motley Fool broker does.
But if you hold shares other than in an ISA, then get shot of your nominee account and open a Personal Crest account (which only certain brokers offer - APCIMS shows you which brokers support that). This is the low cost, foolproof way to have all your rights (not just voting rights) you should have as a shareholder in a company.
See the ShareSoc web site for more details on Personal Crest accounts. Why don't more brokers offer them? Primarily because its more in their interest than yours to have you in a nominee I suggest!
So stop being a patsy and search out those who do.