At the end of The Detectives sketch, Bob (Carrott) says, "We'll be back!"
So is it coming back for a new series? There might be some mileage in that it was billed as "The (Private) Detectives". Now Sherlock Holmes is back on film and TV, it can lampoon that. Like a lot of retired coppers, they could also work in security (perhaps, to make it funny, they could work part-time in a bingo-hall, thinking grandiosely believing they are keeping thugs out when in fact all they have to contend with are old ladies).
If it did come back, they could do this:
BOB AND DAVE ARE CARRYING CARDBOARD BOXES INTO THEIR NEW OFFICE. On the door is a plaque written, 'DAVIS AND LOUIS - PRIVATE DETECTIVES'. A PHOTO OF THEM BOTH BENEATH IT BEAR THE WORDS 'TWO HEADS ARE BETTER THAN ONE AND WE'RE HALF THE PRICE!'
BOTH ARE EXHAUSTED, BUT DAVE'S PRIDE MAKES HIM BERATE BOB FOR BEING SHATTERED AND IGNORES HIS OWN FATIGUE.
DAVE: You can't carry anything, can you? You were like this at the Super's funeral. A hopeless pall-bearer.
BOB: That wasn't my fault!
DAVE: Bob, you dropped the coffin! His body fell out and sprawled all over the floor!
BOB: Just a mistake. Could've happened to anyone.
DAVE: It's like when I saw you walking back from Sainsbury's the other week, heaving shopping bags, your bony arms dangling beneath your knee-caps. If that old lady hadn't stopped to help, you woudld've toppled over!