I thought you could do the IR on a single? As well as the CPL?
Cos you can get a PPL with an IR. I would not want to fly that often IR in a single as you are out of luck if your engine does fail - trying to do a pFL in cloud!!!
As for the IR - the JAR stuff is what they must do but as to order etc, it depends on the examiner and the day and the airport etc... I know people who have been refused an ILS and so done some holding and then a NDB etc.
Top tips - make sure and do it in a quiet time as then you only have to do one hold, if it is busy and you are made to hold then they have to assess every hold which can become nasty!!
Also beware of what to do if your instruments fail - i.e. in the middle of an ILS the flag comes up - what do you do? Abandon it, refer to your secondary instrument (it is tuned in isn't it?), do a Go-Around or just panic??? Many people are not taught that and it could happen so beware!!
Above all budget for at least 5 hours more than you need as there are bound to be issues as with everything in aviation!!