Interesting Steve.
I lamb in June, outside on grass. The ewes are just fed hay, they never taste grain. However the hay is usually better quality than that which you could make in Britain, it is a grass alfalfa mix. I also bale oats into a greenfeed. June lambing is the key, and I speak as someone who has lambed sheep in just about every month in the past in 3 different countries.
The ewes go out in mid April onto stockpiled grass. They then get 6 weeks of the best feed in the world for sheep, or dairy cows for that matter, May grass. They get exercise, which helps with distocia, and they lamb in prime condition, full of milk, in good warm weather. You are not fighting the elements, trying to keep lambs alive. They have lambed at 190% for the past 4 years.
I keep the ram wether lambs until the following January, separating and weaning them early in September when I sell the ewe lambs for breeding stock. The wethers are around 85-100lbs by the New Year, again just on grass and hay.
This works out here due to the low cost of land, though this is changing as the world gets hungrier and commodity prices rise.
I can do nothing about lamb prices, all I can control is my cost of production. It would be hard to get them any lower. The sheep are not pushed and live a natural life too, which is important to me.