Is the primary school a local authority school? In which case, they had every right to be with representatives from the school, because the school is in its control.
If it's a voluntary aided school or academy, it's a different matter.
Sorry, but the question of the secondary school was irrelevant, as were travel arrangements.
The secondary school is responsible for its own admissions criteria. Personally, I don't think feeder schools should be high up on the list for admissions, but it's legal and that's what your MP might wish to challenge. It's happening in authorities of all different political persuasions, so it's not a party political issue. I also don't think schools should be able to set their own admissions criteria. The real problem is that schools have been encouraged to compete with each other and are not allowed to keep places free for children moving into the area. Again, your MP might want to challenge that. What happens (as you've found out to your cost) is that parents from outside the traditional catchment area take places from those living nearer, because they are exercising their freedom of choice. 'Choice' is a daft and unfair policy, because one person's choice is at somebody else's expense. Popular schools can't just keep taking more children.
I would seriously urge you to go to the CAB or, at least, contact somebody on Mumsnet with extensive experience of admissions.