A wanker, literally, is someone who wanks (i.e. masturbates), but generally means someone who is thoughtless, inconsiderate and self-centered. It’s very often used in driving situations, shouted at drivers who have just cut you up, tailgated, etc.
A bleeder is both archaic and fairly upper class – I haven’t heard anyone use this for years.
Bloody is a corruption of “By Our Lady” and as such, is technically blaspheming. It is rapidly becoming inoffensive, and is far closer to damn than to fuck. It is often used for emphasis – “The bloody neighbours were partying until 5am last night”, “Don’t be so bloody stupid” or as an exclamation – “Bloody hell” (if you see something dangerous/stupid etc)