CREATE TABLE table_29135051_3 (broadcast_date VARCHAR, guest_s_ VARCHAR)

when was the episode on which barbara windsor and heston blumenthal guest starred broadcasted
SELECT broadcast_date FROM table_29135051_3 WHERE guest_s_ = "Barbara Windsor and Heston Blumenthal"
SELECT "broadcast_date" FROM "table_29135051_3" WHERE "Barbara Windsor and Heston Blumenthal" = "guest_s_"