I'd say hang in there with routine, its probably developmental. We had similar at that age, taking ages to go to sleep at BT, waking a lot earlier than usual etc. I went down the route of cutting the nap shorter & after 2-3 weeks I could see DS was a complete wreck, he wasn't going to sleep any earlier & he was still EWing and NWing too. I had to reinstate a 2hr nap b/c he simply couldn't cope with less, and so since 22-23 months he's been napping 1-3/3.30 with BT at 8pm. He wakes at 7am. I think they are just at the stage where they realise they can influence things with their behaviour eg delaying tactics at BT & we as parents have to remain strong. I also think that DS's sleep needs seemed to increase again as he hit 2, so hang in there & it might just settle back down again.