For permanent pasture what do others think is the 'right' time to replace the ley with new. What mixes would you use for sheep?

In the UK I have been successful in April and the first half of September. You are a lot further south. Species depends on you view on life - max production or a mixture of grasses, legumes and "herbs". Both I and the goats (so I assume sheep too) like some chicory in the mix, variety Puna. It is expensive but roots very deeply and is persistent. The varieties of grasses and clovers I used in Australi, and the same here, would probably not suit you - Porto cocksfoot, Demeter fescue, Haifa white clover and Genesis lucerne.

Peter,

Take your normal mowing or grazing right up to August, then second or third week in August best time to break it up and sow seeds, if they get away promptly with some rain there will be some light grazing in the backend, and will get a full cropping year the next spring.

I always think that the young seeds are best rested through the winter, and as the soil dries out in the first spring, the roots are strong enough to follow the moisture down, giving a more reliable crop.

Trouble with spring sown seeds is when you get a very dry May, and you struggle to get much production that year. The grass roots are not mature enough to reach down to the moisture.

Burn off the old lay using Clinic etc. Choosing the mix we would use a little early, mid and late varieties in the mix with a bit of clover. September into a firm rolled seedbed, broadcast seed, lightly harrow and roll again. Give a little extra seed for "itself".