Tomato plants ,the leaves are curling up on the sides?

I have 3 different types growing in a row. trained up a 2 meter fence,the one in the middle is the worst.it is a heavy soil type,built up on a 6 inch mound ,plants are about 1 mt apart, mulched with pea straw , well watered at night ,it's 35 deg c,windy lately but protected by lg shed ,the middle one has just started getting blossom end rot. I live in southern nsw australia, wagga area. cheers.