Hi, I've just walked into the kitchen to discover my dog (who eats anything in sight) has spotted a cake (bara brith) which had sultanas in and he's eaten it. There was only 1 slice left....how many sultanas will be too many? Should I just keep an eye on him or take straight to vets? I stupidly thought he would be happy enough with his kong for 10 minutes and wouldn't try raiding anywhere else 