Hello again. Just tried looking for thread myself and is long winded so here it is ;
Was on a parallel thread to this yesterday, so in brief:
We had same problem with DD1.
HV said it is very common (as you can tell from answers!) and it seems to be a sort of fear of pooing into 'empty space'.
Bribes are ineffective because it is just asking too much of them to go straight from nappy to loo. (This is what I hadnt got my head round- I had a fabulously tacky tiara set waiting for her first poo and still nothing doing, I couldnt understand it..)
She suggested we break it down into small steps and reward those steps. (I think it took about a month)
For us the steps meant pooing in a nappy - but not in the cupboard. Pooing in nappy near the loo. Pooing in nappy on the loo. Getting on the loo trying 3 pushes, then she got a nappy.
Finally 3 pushes and slightly runny tummy and she went. All a bit emotional. Was fine from then on.
Concurrent with all this was 'practise sitting' where you get them to sit bare bum on the loo with no expectation of anything happening - ie no pressure at all.
You read them a story, or give them things to do like blowing bubbles or trying to blow up balloons as this leads to pushing action.
This is to hopefully get them to be less anxious about the whole loo experience especially if things have got a bit pressured.
When she then started going I bought a bunch of pretty beads and she got one everytime she did a poo and we threaded her a 'poo necklace'.
A year on she is absolutely fine about pooing at home or when we are out.