2yrs 7 month daughter holds wee in for hours and refuses to wee at all on potty.

[Malteser101]

I tried potty training a couple of months ago and this happened. I decided she wasn't ready and left it alone, but have recently started again with the same result. She loves wearing big girl knickers and will sit on a potty or toilet with encouragement but does nothing at all on it. I tried rewards, I've also tried not putting her on too often vs putting her on all the time.
Today I was certain she was due a wee and within 30 seconds of getting off the potty she weed on the floor.
She is generally quite obstinate at home but very accommodating at nursery so my current plan is to send her into nursery with pants on for this week and see if they have any joy, if not postpone and try again. Any suggestions will be gratefully received though!

I thought I'd give an update. She carried on doing exactly this for 14 full days, at home and at nursery .... Then on day 15 it was as if a switch suddenly flipped in her head and every wee has been spot on, no accidents for a full 6 days now... Go figure.