After 20 years of exercising a right such as access or right-of-way or parking, then you can claim the right to continue to do so as an easement under the Prescription Act.
The 20 year period applies collectively by adding together your use and any previous use.
You would need to get the easement registered against the deeds of the land or registered as a land charge if the property is unregistered.
Once you have the easement to park, you can then take the other neighbour to task over obstructing your vehicle.
Even before you have the easement to park, you have a claim against the neighbour in private nuisance if he is doing this and it is quite simply a nuisance whereby you have to ask him to move his car every time you want to move.
As it is at present, there is nothing to stop him parking in this space.
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