I've just phoned my vets again now and spoke to the other vet nurse. She was wondering whether it's possible that she's ingested something before they took her in? Usually fitting is caused by a toxin and the worse culprit is Bob Martin flea stuff. If she was milbemaxed whilst in the vets and fitted on the way home, it wouldn't happen that quick as it would have to be digested first for a reaction. The jabs possibly but again, some would react, some wouldn't but my vets haven't had any reacting to the jabs either but the Leukaemia one then yes, that is likely.