Well, I've implemented a method now, its subject to change.. but to seems to cope ok.
A) Stands beneath at the platform would crush him?
The platform comes down and does some damage. When the player is damaged they get a grace period of 2 seconds of invunerability to sort themselfs out (flashing character during this period).
The platform carries on through the character but this would seem ok since the character is flashing.
B) Stands on it and gets pushed into ceiling?
Not sure I like this one, but.. the character gets delts damage and starts to flash as above. Since the ceiling is static and the platform isn't the character gets pushed down through the platform. This could lead to cheats if (my) poor level design is used

C) Stands on the edge and gets squished between two platforms.
To try and stay consistant the same happens as with B) The character is pushed through the platform they are standing on, but is dealth damage which give them the grace to be pushed through.
I think this method might give me a bit of "feature" to play in level design but also doesn't feel too terrible..
What ya think?
Kev