Just posting this because it might help people be more relaxed about their children if they are late to use a potty.
My dd2 has been very continent for months. Dry at night since before 2. Able to hang on from about 2.5. However, she was very reluctant to sit on a potty or toilet and until Sunday (aged over 3.5) she has insisted on having a nappy put on when she needs a wee or poo.
Since 3.3 she has used the little toilets at nursery and last week she was staying with a friend and used their toilet.
Finally, on Sunday she nonchalently said that she was going to use her potty.
So, having been relatively relaxed about the slow progress we've now 'got there'. It just takes courage to ignore all those who can't understand why you're humouring a small child.