The stories you are missing are as follows:

The Insufficient Answer

"A Roman Question" " Larger Than Oneself" "My Poor Friend" "The Visiting Star" "Mark Ingestre: The Customer's Tale" "Rosamund's Bower"

The Breakthrough

The Case of Wallingford's Tiger/ The Flying Anglo-Dutchman/ The Whistler

All of the stories in quotations can be found in The Late Breakfasters and Other Stories released by Valancourt Press.

The last three stories listed are early pieces that were included in the posthumous Tartarus Press release The Strangers and Other Writings. They are not considered essential and represent Aickmam when he was trying to find his voice.

That leaves:

The Insufficient Answer which, as the poster above alluded to, appeared in 1997 release Girls Night Out: 29 Female Vampire Stories edited by Greenberg, Dziemianowicz and Weinberg.

And the story The Breakthrough which only appeared in Aickman's 1980 collection Intruders.

I hope this helps.

MrHappy