Blocked Shared Driveway

You live in a townhouse with a shared driveway. Your neighbour's visitors have parked across the entrance several times this month, and yesterday you missed the start of a lecture because you could not get your car out. The neighbour is friendly but may not know. Speak to your neighbour: explain the problem and suggest a solution for future visitors.

Hi there, sorry to catch you on your way in. I just wanted to mention something small about the driveway. A few times this month your visitors have parked across the entrance, and yesterday I was stuck for twenty minutes and missed the start of a lecture. I'm sure they didn't realise it's shared. Would you mind letting them know there's plenty of space on the street around the corner? I'm also happy to put up a little sign if you think that'd help. Thanks, I really appreciate it.