Compaints should be directed to OFCOM, the broadcast watchdog.
“Deception”, by the way, is illegal. If Channel 4 were practicing it, they could be prosecuted.
In terms of the “vague” reference to the date the programme was made, yes, you do have to be reading the credits at the end of the programme, whereas the BBC have inserted the date into the body of the programme. This requires time in an edit suite. The BBC have in-house facilities so it doesn’t cost them anything. All C4’s programmes are made by independent production companies who have to buy in facilities.
They are unlikely to do this when the dates are clearly quoted. Which they are.