My girls been in vet today having xrays and scans for these upsets she keeps getting. Nothing abnormal was found and the gut wall was normal thickness.  The vet is suspicious of canine epiletoid cramping syndrome, which it appears, is seen in Border Terriers. Personally I don't think its this. My girl shows no neurological signs at all.
I just wondered if anyone here has any experience of this condition

http://www.borderterrier-cecs.com/
http://www.youtube.com/watch?v=014oEpS-14k