improving clay- sharp sand? or Gravel? or both?

Am getting some fence panels delivered soon from local merchants. They also do aggregates and as I am having to pay for delivery may as well get other stuff as well. So.... for my terrible clay soil I am getting 2 tonne of top soil and was going to get 2 tonne of sharp sand as well. I was going to get grit but they dont seem to do it. they do 10mm gravel. What do you think? all sand or a tonne of sand and gravel?

 

Do they do grit in smaller bags? Maybe get a dozen of those, as well as the sand. Mix the sand and gravel in a barrow before putting it in the garden.

Rusty.