Hello, I am a soliictor with 20 years experience. I will try to help you with this.
I am afraid that there is not going to be a practical legal remedy for you here. If there are no parking restrictions on the mews this is is an example of selfsih bef=havoiur r
Sorry sent before finished, In the absence of parking restrictions If they are not not blocking the highway then therei snothign you can do in law. Th ebest suggestion I can coem up wiht is 2 large and eheave plant pots outside your fornt door to make it impssoble ro them to park