Sorry all, the above post was the result of much frustration. In reply to peoples comments I realise the yun is more like a Leonardo, when I mentioned the uno just worked I wasn't referring to shields, just the software serial. Shields I realise can be wired up on a breadboard and made to work, have done this but still minorly annoying. Saying RTFM is never helpful, could anyone maybe help me by letting me know why an rfid with software serial only works on pins 10 an 11 for instance? I'm all for reading the manual, but can't find a reason for this... Thanks in advance for any help and sorry for venting.