Just posting in case it helps someone who is worried that they are "making a rod for their own back" (when I am king that phrase will be illegal).
DD is 22 months. Up until 14 months she was bfed to sleep, when it suddenly stopped working (which was a bit annoying, despite me worrying before that that I would have to do it forever) so then I would give her a feed then DH would go in and cuddle her until she fell asleep. This was taking an hour or more most of the time so a week or so ago we started just leaving her and - unbelievably - she just chats to herself for a bit then goes to sleep We co-sleep so she sleeps on our bed until we go up, so we've never tried it before as I assumed she'd just get out of bed but she doesn't. Amazing.
If 22 months of parenting have taught me anything, it's that it's all just a phase so it could all still go tits up. I also know all children are different and the plural of anecdote isn't data ... but certainly for us, cuddling DD to sleep for all of her life hasn't rendered her incapable of falling asleep by herself. Hope that someone finds it reassuring!