It is sensible to order the offender to go to an area far from the victim, in order to continue his imprisonment in house confinement, or with whatever limiting conditions the court and probation service have agreed for him.
Technology is more sophisticated than the basic ankle tag. He could be ordered to remain inside, with cameras to check no children, for instance, are allowed into his house. He could be allowed to get a job, but only to travel directly to work and back. He would, for life if necessary, have to check- in, at instructed intervals and also at random, using his phone and demonstrating where he is and who is with him.
Technology could prompt him to report, and could monitor the films, so it would not need a probation officer to chase him up, unless the automated system had sent a warning about him being in breach of his terms. In that case,the probation service would alert police who would readily pick up his whereabouts, electronically, so it would be easy to arrest him.
He must also have a long-lasting drugs implant, if his offending is related to substances or alcohol, or if he needs behaviour-calming drugs, to reduce his interest in problematic sex or violence or children. If the side effect is reducing his interest in most things, so that he is rendered apathetic about everything from cake to harming people,it will be to his advantage, in saving him from himself.
Women can have very long lasting contraceptive implants, and it is absurd that currently, even in prison, convicts are allowed medicine by mouth. It's hard for anyone to manage a drugs regime by mouth, at home. But if behaviour must be controlled by drugs, as an alternative to putting the offender in a cage for life, then implants are the only option.
The call for long jail sentences ignores the thousand pound a week cost. It need cost virtually nothing to keep a convict unable to re-offend, using drugs and technology.In the area he is sent, it ought not to matter what his offence was, if he is now either confined entirely in his residence, or else is out on extremely strict and technologically enforced conditions.