I have now received the same leaflet. Since your location says 'Nottingham' and I live in London, I'm guessing this leaflet delivery is reasonably national and therefore the group behind it has considerable resources.
I'm pretty disgusted by it because it is so clearly designed to mislead people into thinking it's an impartial/educational leaflet when on a more careful read it becomes apparent that it's actually part of an 'out' campaign. The 'facts' themselves are not entirely correct (as I noted earlier, one of them - the claim that the EU costs us £350M a week is simply not true) and are clearly carefully selected to promote the 'out' argument, but nowhere is this indicated. Even when the facts presented are literally true, accompanying context that would indicate the true picture is omitted (Example: 'You don't have to be a member of the EU to trade with it' - strictly true, but doesn't mention that you'd still have to negotiate agreements/conform to much of EU law/etc.) And of course, as
Domh245 noted, there is no explicit indication of who is behind the leaflet.
Many out campaigners like to label the 'in' campaign as 'Project Fear' but it seems to me that the various out campaigns can themselves be very accurately described as 'Project Lie' or 'Project Mislead'