'Naughty' when more than one adult!

[dribbleface]

My Ds is a lovely energetic little boy (2.5yrs). However when both me and his dad are around he turns into a devil. Hitting, screaming, refusing to eat and general stropping about everything.

Yesterday I took him to see his adored GP's and he was good as gold, dad showed up and in my opinion his behaviour was terrible, he smacked me round the face at one point . At home he sits on the mat for that type of behaviour, so I did this. My parents have since made it very clear they disapprove of him having to sit out at their house (i do not expect them to do it and to be honest they are not likely to need to as he is an angel there and at nursery)and in their opinion his behaviour is not naughty. He is their 1st grandchild and he can do no wrong in their eyes.

So was i wrong to sit him out, should i not do it there? I'm guessing the playing up when both his dad and I are around is excitment/attention etc and where possible i do ignore attention seeking behaviour but I will not be smacked around the face my Ds.

Fed up!