I have insterted the following css from the out of the box css file and all is well
.e-chkbox-wrap.e-focus div>span {
box-shadow: 0 0 2px #cbcbcb
}
.e-chkbox-wrap div>span {
border-color: #bbbcbb;
background-color: #fff
}
.e-chkbox-wrap .e-chk-image {
background-image: url(images/checkedtick.png);
background-repeat: no-repeat;
background-position: 0 -50px
}
.e-chkbox-wrap .e-chk-image.e-chk-indetericon {
background-image: url("images/gradient.png");
background-repeat: repeat;
background-position: 0
}
.e-chkbox-wrap .e-chkbox-small .e-chk-act .e-chk-image.e-chk-activeicon {
background-position: -1px -21px
}
.e-chkbox-wrap .e-chkbox-medium .e-chk-act .e-chk-image.e-chk-activeicon {
background-position: 2px 2px
}
.e-chkbox-wrap .e-text {
font-family: Segoe UI;
font-size: 12px
}
