as mentioned above, UK blue disability permit for automobiles are accepted in WDW...
however, for people who do not have a blue disability permit (those from countries that don't use the blue disability badge), there is an alternative when parking your rental car..
you will not be permitted to park in the handicapped parking area. To park in that area, you need a blue permit.
But you can park at the beginning of each line in the parking lot - so that you're right by where the tram picks up...
to be able to do that, you need to get a GAC that permits parking at the beginning of the row in the parking lot.
Guest Assistnce Cards were only used inside the 4 Theme Parks.
Apparently they have recently added a new stmp for those who need to park close to the tram stop.
Even if you are not at the front of the row, the tram lets you off at the park entrance the closest compared to the buses and walking from handicapped parking. So, even if not at the front rows, the walking using the regular parking lot and tram may actually be a shorter total distance than parking in the handicapped parking areas.
A GAC is not used for parking.
If you need to park closer to the tram and do not have a handicapped card, you will need to speak with the CM that is directing cars in the parking lot. They will do their best to assist you.
You can also use the drop off points in the parking lots. One person can drop the family off and then can park the car and ride the tram in.

Each park does have a drop off point. Let the CM at the pay station know that you want to drop someone off and thy will direct you.
If you do not have a parking permit or a GAC AND have a mobility device that can't go on th tram, tell each CM directing traffic that you have mobility device and that you do not have a handicapped parking permit.
Thanks for the information. I won't be afraid then to use my parking pass then. I usually rent an
ECV at Disney because we have no way to get around or the room for it in our room.
Since we are only going the one day I am going to see how I am with my walker and if not I will again rent an EVC for the day. I am not sure what my niece is going to do. I am going to talk to her about the EVC for the day.
Does anyone know what we could do with our walkers for the day though if we rent EVC's? Since it will be a bit of a walk to Magic Kingdom we or at least I will need the walker to actually get there. We are only going to MK.
tigercat
Keep in mind that they may run out of
ECVs to rent if you are needing to rent one after about 10 or 10:30 am.
So, since it is only one day that you plan to go, you may want to just get there early and rent one anyway.
When you rent an
ECV from Disney they are glad to store your walker for you and get it back to you when you return the ECV.

Just what I was going to suggest.
Since all the OP's questions have been answered, I am going to close this thread.