Definitely get her checked out.

Have you tried reusable pull ups (try Genesa Forge or WomButts)? That way she'll still be in something that looks like undies, that she can pull down if she needs to use the toilet, but much easier to change and will contain any wee or poo. Takes the stress away and turns it back into 'not such a big deal' for you or her.

You could also try setting an alarm every hour - we used the duck ringtone on the phone - and take her every time it goes off. DS used to hate us asking but didn't mind ducky asking him!

Definitely keep going the no pressure route as you don't want her anxious about going to the loo - that can cause even more problems.