Chilli and IO540: the term Minimum Vectoring Altitude in not recognised in the UK and should not be used; it does not appear in MATS Part 1 and thus has no 'legal' definition, so where Chilli gets his defintion from I don't know.
There is no such thing as a Radar Vectoring chart; having been re-named 'Radar Minimum Altitude Chart' for a short time, the term used now is 'Surveillance Minimum Altitude Chart'.