There’s a bit of legal interest here, because the only vehicles permitted to use flashing lights are those working by the side of the road or being used by emergency services. The law is completely silent as to auxiliary lights which are modulated to flicker.
Use twinkling auxiliary lights, which fall on the correct side of the law.
Don’t do this
Use strobe or flashing lights. Ever. You won’t get points on your licence, but it can carry up to a £5000 fine.