[landroverroy]

 Yes that was very good and useful.

[ewesaidit]

Thanks to all for the replies - especially 'Me' - excellent explanation of the difference between the two types of prolapses. 
When the vet was putting the 'lamb bed' back in he got me to go in and help push the uterus further back and he then went back in explaining it was to make sure the 'horns' were pushed back fully.   

I did read up on it just after the event and there was mention of a lack of calcium possibly being a contributing factor or perhaps an infection which caused irritation causing the ewe to push. The vet didn't suggest calcium and thought it was just one of those things.   She only had a single which was small and this is her third lambing so can't imagine she had to push hard!  Also, maybe of interest is the fact that she did have something odd in the afterbirth that looked like a lamb that had died very early on.   

Still time to decide .... very useful to get everyone's views - if she is bred again and I want to ensure that a lack of calcium isn't a possibility then at what stage do you inject it?  in the immediate run up to lambing/once started lambing/immediately after lambing.

thanks again