I found not many got in. And (after watching them for an hour or two) the bees sacrifice themselves to get rid of the ants. So one bee will come out attached to one ant and fly off to get rid of it. A bit heartbreaking.
Spray will kill the bees.
We…
Surrounded the hive in cinnamon.
Put the hive on a knocked up stand.
Put the legs of the stand in oil (in big tuna tins).
Then put grease (that doesn’t melt) around each leg. Pictures of the type of solutions I found.
Apparently ants can wipe out a hive.
Also, if they are meat eating ants (and if they are attacking the bees it’s likely) then the active ingredient you put in tick treatment for dogs (fipronyl) can be mixed with mince and put in the ant trail (away from dogs, kids etc). They will take the poisoned meat back to the nest 
Grease in the cap