Just registering annoyance would have been enough for me. To put in an actual complaint I’d have had to spend more time thinking about having all tv channels the same and all radio channels the same was overkill. Then there was the loss of Radio 4 Extra until Monday morning. Life’s too short. I’ve got better things to do.
My comment to the BBC was along the lines of - "Are there any viewers that can receive either BBC 1 or BBC 2 but not both?, if the answer is no then nobody in the country benefited from the simultaneous transmission on both TV channels"