That's the seatbelt and airbag warning lights; given that they are flickering I'd suggest looking for a loose connection at the wiring plugs under the front seats.
Bear in mind if you have any load on the passenger seat it will trigger the occupancy sensor, so unless the seatbelt is plugged in that light will be on, and the bing bing noise will start once the car starts moving at any speed.
The airbag one will probably need multiecuscan to clear though (and is an MOT fail if it's still on)