My father served in the RAOC during WW2 and this was one of his 'party pieces' ie songs sung at family gatherings. I always suspected that it was Music Hall song and it's pleasing to be proved right. It wasn't just Woodbine that were sold in packets of five, Players and Capstan were too. Whiffs were definitely small cigars so I imagine the reference in the lyric is to puffs of Woodbine smoke rather than another brand of cigarette or cigar. 'Wobbles' is surely short for 'collywobbles' a slang term for a tummy upset.