Hi Ladies, need your advice/input again!

Kai has always been a terrible sleeper, he has slept through about 15 x in 2y3m. Since he was around 1yo he would go into his cot after a cuddle and would go straight to sleep. The fun and games started about 10ish usually, but we were very grateful that he went to sleep easily. It was another story entirely for the first year, but that's another tale.

Anyway, for the past 3 weeks it has been taking us an hour to 90 mins to get him to sleep. We lie with him in his bed (he started sleeping in the big bed about 4 wks ago - totally his choice) and still he won't/can't fall asleep. If we move a muscle he's straight up, wanting to know what's going on. During the day he is also very clingy. He's fine if we're nearby, but we can't pop into the house or go around the corner for a second. He trots along behind us, crying as if we're trying to run away!

His sister is now 11 weeks old. I thought he'd gotten 'over' the issues when she was about 8 wks. Is this related to her arrival, or is there some sort of 'wonder week' at this age? We are being patient and tolerant, we stay with him, he comes in to our bed once we're in it. But we're getting pretty frustrated, he's not settling down in spite of all our reassuring. I don't mind sitting with him while he drops off, but I don't understand why he fights sleep for so long.

Grrrrr