Allotments 4 All

I know that in order to get the berries on skimmia plants you have to have both male and female plants.  I was wondering what is the distance they need to be get pollinated.  I was hoping to plant Wakehurst white (was fructo albo) and Kew Green.

A winter flying insects fight apart!  Probably within the same garden in a normal size plot would be enough.

Thanks, Eric, catalogues just say "nearby".  The distance would be more or less 60 ft.