Chosen Solution

I note that iPad 2 Bluetooth/Wi-Fi Antenna says its not for the EMC 2560 model, but is there a suitable antenna available somewhere?

I think this is it: http://www.powerbookmedic.com/Wireless-3

I’ve replaced hundreds of iPad 2 antennas and never worried about which model it was. The connection is the same on them all and the mounting is the same. There are no electronics to deal with, its all analog. You should be good to go. I do remember seeing a couple iPad 2.5s with weird antennas. If you could post a pic of yours, I could tell you 100%