At no time have I ever presumed that I am always right.
But untrained PPL VFR pilots whose only experience of an ILS approach is on a PC are not the people who should be practising something they've never been taught - particularly at a busy airport in Class D airspace.
What on earth do you want 'radar vectors' to the ILS localiser for in VMC if you're not going to practise an ILS? If you just want a straight in approach, ask for radar vectors to a straight-in from 4 miles final, or words to that effect.
Plus, of course, the aerodrome might well charge you for the ILS approach in any case - even if you're not qualified to fly it.
Flyin' Dutch, your 'half visual, half instrument' technique is one of the most dangerous techniques known to man......
IO540 - If the ac is fitted with DME, it makes sense to teach its use as an en-route navigation aid during PPL training. But ILS is not an 'en-route' aid, it is for precision instrument approach flying. All my ac are fitted with GPS - we also teach how to initialise it and read off 'present position' in case a pilot becomes lost with an unserviceable transponder, but we don't teach ab-initio PPLs how to use it for navigation.
ratt - the average military ATCO hasn't a clue about the requirements of Rule 6 & 7. So, even though he/she might grant your request for an ILS approach, it's up to you to know the rules which apply to your flying when making the request or flying the approach.