IOM plates ***MAN and ***MN etc are registered with the IOM Department of Transport. They are not recorded with the DVLC. Tax rates are similar but again you pay the Tax in the IOM
Cars registered in the IOM need to have keepers who have their address in the IOM.
This also applies to the drivers.
If you have an IOM Reg in the UK or UK reg in IOM you have to re-register (export) to your new residence usually when the tax is up for renewal.