How many shows did team David consist of vernon kay and dara ó briain
CREATE TABLE "table1_23575917_8" (
  "episode" text,
  "first_broadcast" text,
  "davids_team" text,
  "lees_team" text,
  "scores" text
);
SELECT COUNT("episode") FROM "table1_23575917_8" WHERE "davids_team"='Vernon Kay and Dara Ó Briain';