Referendum

I thought this question would have been asked already. We spent all of June touring abroad last year we have not booked any crossings yet but thinking of repeating the same this year. We used postal votes in the election last year so that's not the problem
but my question is how many weeks before June 23rd will the postal votes be sent out? I am thinking if we are abroad a relative might have to forward our votes to a campsite for us to send back. I know it's only two votes but it's an important issue not least
the effect of the exchange rate on our little jaunts abroad.