Just to update this, we ended up doing it all in a day, boy loves it, and for not staying it cost me £60 for a Jurassic park Lego set (although tantrums were had as he really wanted the Jurassic park gates for £200, no way was that happening)
My Great niece and her family were there this week for the 2 day stay over. They said they had a fantastic time and would really recommend it to families with children.