Luke still hasn't explained the difference between a lad and a geezer.
Geezer is East London/Essex, essentially. And can just mean "boy" ("who's that geezer?").
Just like in many places "lad" is more like "boy" (i.e. male children, teenagers and young adults) than the macho beery NUTS mag reader.
But adding "a" in front of them ("what a geeze", "what a lad!") changes things - nobody really says "what a geezer" ironically, unlike "lad" (its very easily an insult). Otherwise it can mean "legend"/"hero".
And thus ends my catechism.