Thanks so much for all that Mushroom

What time did your son stop taking naps? I think it's still too early for DD to drop her nap and she is good with her naps. Sometimes she resists (a recent development too), but once I leave the room she's either quiet and asleep within minutes or will happily have quiet time with her soft toys and books. So I'm not so keen on dropping it yet as it's my quiet time too!
The problem is not getting her to bed, she loves her shower and bedtime story routine with us, and we've always had a regular routine so consistency doesn't seem to be the problem. The problem that has developed is that as soon as she see's me leaving so stands up and wants more cuddles. If I stay and give her more cuddles she clings so tightly and then will only lie back down if I stay. If we do manage to make it out before that happens, the crying starts not long after we leave the room.
We've tried leaving her to cry for awhile but she just doesn't settle down on her own anymore and can cry for hours. There's nothing wrong other than her wanting us in the room with her, because as soon as one of us goes in she's quiet and happy. If I go in and ask her to lie down she does, but will stand and cry as soon as she sees me going again. I've tried staying in the room till she falls asleep, and that works, but is that a bad habit? Sometimes she will cry out when she wakes again and sees I'm not there, but sometimes she will then happily sleep through. I have to wait till she's in a completely deep sleep to leave too. If she's closed her eyes but isn't fully asleep, once she senses I'm not there she's up and crying again so we start from square one.
I just don't know if that's the right thing to be doing? Will she then get dependent on having me in the room to sleep? Should I be doing the cry it out method? We did teach her self settling at a young age by using controlled crying, and that only took a day or so and she never cried longer than 15 mins before she got the hang of putting herself to sleep. But this is completely different as she is so determined!

I don't mind trying crying it out but at the moment I just don't see it working, but perhaps I need to stick it out more? I do see we need to choose an approach and stick to it, and like you say have consistency with how we handle it. I'm just unsure which approach I should be doing.
Is it possible she's started getting scared of the dark you think? We just introduced a sort of night light (projector light that projects coloured stars on the ceiling that move and change colour). It worked at first, but we had a repeat performance the past 2 nights again so I'm now thinking it's a bad idea and could keep her awake!?Sigh.
I've always had such good instincts about what I needed to do when she changed things on me, but I feel a bit lost on this one!
I think I will take your suggestion and start putting her to bed later. At the moment we do the shower at 7pm so she is usually in bed by 7.30pm. I might try pushing the routine out by 30mins. But she does seem tired come 7pm shower time, so again I'm not sure if that's the right course of action. Still leaves me with the problem of what action do I take when she starts her grizzling and crying when we go to leave the room...
Sorry for all the long posts, half of it is no doubt me just voicing my thoughts to get it off my chest.

I would love to hear what tactics you use with the crying.