@Liv
Parking where I live is a complete nightmare. My road is a red route. My house would originally have had space for a driveway out front, but at some point (decades ago), the owner sold half of that space to the next door neighbours. You can see that the wall between their driveway and my skinny garden, cuts significantly in front of the house, making my space just slightly too narrow to fit even a very small car.
There is not much I can do about it. I tried asking previous neighbours if they would sell me back the land, but they didn't want to. My new neighbours don't even own a car and rent out their driveway instead. However, the property prices have shot up around here since I bought the house, so even if they were willing to sell it to me, I wouldn't be able to afford it!
Luckily, very, very few of my guests come with a car. In fact, I can only think of one and he was local so had a parking permit for relatively nearby and mostly used his bicycle anyway. What is more of a problem is guests arriving by taxi and needing to unload the luggage. There used to be a loading bay right outside, but TfL got rid of that and all the other bays nearby. The nearest parking is around the corner and is metered/residents only most of the week. I usually offer to go round and help bring the luggage to the house.
If guests did need to park at mine, I could offer two options. One would be to rent my neighbour's driveway, but this would work out very expensive for a long term guest and the driveway is usually fully booked (people are desperate for parking around here). Or, I could order a huge stack of day permits for the guests to park around the corner. This would also be expensive for long stays, but about half the cost of parking next door. Other than that, there's really nothing I could suggest.