the new SD card shield is just a generic shield from one of those really cheap sites.
Micro SD Storage Board Micro SD TF Card Memory Shield Module SPI Arduino D22537
its working with no hardware issues as far as i can tell. I've got it wired to the mega pins 50-53 (these are the default SPI pins on the mega 2560 53 is ss so CS from the SD reader is there now) so its ok if it doesn't release it nothing else it going to use it.
the only issue I'm having now is reading the file correctly but that's what my new thread is for.