Hi
Not sure if much help or not, but i know you have to pay for a plot reference. What i do is if you have the grave reference is.
Go to a certain area and pick up a reference from a grave stone, you will find the grave reference on the bottom back or side of a stone.
If you do this random you should be able to pick up the area of your grave reference.
You will find very old graves don't have the number but ones near to will, just follow the numbers, allowing for spaces with no stones.
Hope this makes sense, its better than paying, and a lot more fun. Spent many of hours finding my relatives without maps, just the grave ref.
Suee