Ipad Background

Hi

Hhave a problem with background image. Set to fixed position and works fine on desktop. When I scroll down page background image shows all the way.

Site is fine on ipad other than background image which does not fill screen as I scroll. Seems like the ‘fixed’ control has gone off. Soon as I scroll I get standard blue background following onto after image bottom is reached.

Cant find a solution or answer in topics. Any ideas would be appreciated.

Thanks