Wakefield houses both category A and B prisoners.
https://www.justice.gov.uk/contacts/prison-finder/wakefield
Now it does. But the prisoners are is separate facilities. They built some kind of a supermax thing in the 21st century that can house 100 Cat A prisoners. The regular facility is for cat B. The new supermax part is for the bad of the bad so they are not allowed to mix. They mainly send people who got into fights in the past or are expected to get into trouble there.
Housing A and B together would defeat the whole purpose of the classification system which is supposed to take into account who is the most dangerous not only to the public but also to other prisoners and guards.
Mike has already proven himself to be a prolific liar who seeks attention. Part of how he does that is to try to play up his friendship with Jeremy and also how active a role he has played in trying to free him. He claims to have been intimately involved in every step of the appeal proceedings and defense experiments. This culminate din his greatest lie- his nonsense claim that he stole a photo of Sheila's body on bed from Jeremy's lawyer because Jeremy's lawyer refused to use it. This is ludicrous enough but what does he claim he did with it? He claims he mailed it to Jeremy. He mailed a letter to Jeremy claiming he enclosed this photo with the letter though he enclosed no photo. Then when Jeremy said it had no photo he claimed police must have stolen it. Why would he mail the photo without making a copy for himself at minimum or scanning it? The whole tale is an obvious lie to inflate Mike's value and Jeremy thought as much because this seems to be one of the things that caused Jeremy to tell Mike to leave him alone. Another was Mike asking Jeremy for a photo so he could then use the photo to say what great pals he is with Jeremy.
Jeremy suggests that he had little relationship with Mike and that Mike was just trying to get cozy with him to pretend Jeremy and he are great buds and to use that claim to garner attention and achieve fame. While Jeremy is hardly trustworthy I believe that he and Mike had few dealings and that Mike begging to take possession of the documents that were scanned by the defense and no longer needed allowed him to read the documents and then claim he knows more than everyone else because he had a close personal relationship with Jeremy.
I have little doubt Jeremy would correspond with Mike and try to use him to his own ends but it seems Jeremy realized Mike was trying to use him so got pissed off and ditched him upon realizing he was of no use to Jeremy. Much like he ditched and turned on others upon deciding they were no use. he corresponds with plenty of people Mike is no exception. If Mike were a woman he is the sort who would try to marry a jailbird for fame and even make up that they knew eachother longer than they actually did perhaps even claiming they met before the murders.
Even if they had a close relationship though it would not mean anything to me. Jeremy would be making up BS to feed to Mike while Mike would be making up BS to feed to Jeremy. You could not trust that they told eachother the truth about anything and if they publicly reported what the other said to them you could not trust that they were accurately conveying what the other had told them. For this reason I never bothered to challenge Mike about personally meeting Jeremy in prison and interacting with him. Even if true it would mean nothing so wasn't worth bothering with.
It was much more fun ripping him apart on his lie that he stole the photo from Jeremy's lawyer and mailed it to Jeremy in an envelope that stated it was a privileged communication from his lawyer even though he is not a lawyer and thus the privilege could not possibly attach.