“This isn't the 18th century, sorry to burden you with that”: Er, irrelevant for the purpose to show that Death Penalty is a deterrent or not. The past centuries with heavy death sentences (even for collecting dead wood in forests) show as it is not.

“Using paedophiles and saying they can't control themselves is ridiculous & rather sickening if you can pass them off for what they do.” Two things: mad persons can’t control their impulse (and that why they have to be follow even after jail or psychiatric units. You don’t do that with “ordinary” criminals.), so dismissing this as ridiculous is not good enough.
I don’t intend to “pass off” for what they do, I just pointed out that in case Death penalty is not a deterrent as they have no choice in their madness.

“The ones having an affair are killed for having an affair, then yes it would still be a deterrent to others”: Er, do you means the killed lovers are a deterrent for the others who want to have an affair?
And no, it doesn’t work. Still a lot of people are engaged in affair…

“Why would killing someone mean having to kill loads of people to save money”; Er, it is one of your point in favour of Death Penalty. But due to the little percentage of people de facto due to die, if you want to save money you have to kill more people than the few hundred per years… Simple maths…

“Justice to everyone but the criminals victims, nothing can be done about the victims, but it is a justice for there victims in a way with the thought that there nightmares, there killers or injurers etc. have been removed, if a victim can watch from above after life, then who knows they could see it as a justice, I would.” Well, I do agree on your first point. The reparation of the victims is one part missing in the actual system.
However revenge is not justice.
Does a drunken driver should be executed if the survivors want his head because he killed one of their loved ones? According to this line of thought he should…

“they get more money spent on their meals than school children, they get xbox's too, soon prisoners will get ferrari F40's because there will be complaints prison life got boring.”
That is because politicians know they won’t go back to school but they are not sure about jail…
Joke apart, the sentence is privation of freedom, not something else. You can give me all the X boxes of the world I won’t like to be en cage.
The fact is my sister did work in jail as a nurse when temping. If your idea of 5 people in a cell on 4 or 5 square meter is your idea of paradise!!!!

“Case double closed?” Not at all. You answered to none of the objections:
Death Penalty is not a deterrent, doesn’t save money, give justice to families.