Hi Jo
I have only recently joined this forum so only just read your post. I have the same challenge at the mo. I have had baby T for the last 8 wks, he is absolutely fine, happy and smiling while he is sat on my lap or attached to my hip but as soon as I put him down to play or in car seat etc he cries and he doesn't stop crying until I pick him up again. He will play for short periods on the floor if I am sat next to him.
I do leave him because it is not practical or fair on the other 2 under 3's I look after to be giving all of my attention to him. Also I have to prepare/clear up meals etc. His parents are lovely and did work with me by leaving him to entertain himself while at home one weekend and he was a lot better on the Monday, however they didn't carry on and he slipped back to crying for attention all the time!! I am giving it another couple of weeks and the parents have promised to help me out by not picking him up constantly and of he carries on crying I will have to consider giving him up for the sake of the other children I care for and my family's happiness. I don't know what else to do, I just think he is a miserable baby unless he is getting full-on attention, so I sympathise with you completely and I'm glad ther's someone else out there with the same problem.