I’m presuming you’ve not met your neighbours yet? Just go round, introduce yourselves, explain you’ve just moved in etc.
Then politely ask if they know who that car belongs to. (It’s possible, only being in the house a week, you wouldn’t have noticed who was putting it there). He will say it’s his, and hopefully will realise it’s blocking you. It’s possible he had an agreement with the previous neighbours, but at least then, you can get the conversation going, and get a feel for the type of people they are.
That should put an end to it. If they are difficult with you, could you contact the previous owners? They should have informed you of any acrimony. It’s law now I think.
Hopefully, it won’t come to that, they’ll just apologise and move it. All the best to you.