Well, the ANO states:
28 (1) Every member of the flight crew of an aircraft registered in the United Kingdom and
every person who engages in flying for the purpose of qualifying for the grant or
renewal of a licence under this Order shall keep a personal flying log book in which
the following particulars shall be recorded:
(a) the name and address of the holder of the log book;
(b) particulars of the holder’s licence (if any) to act as a member of the flight crew of
an aircraft; and
(c) the name and address of his employer (if any).
(2) Particulars of each flight during which the holder of the log book acted either as a
member of the flight crew of an aircraft or for the purpose of qualifying for the grant or renewal of a licence under this Order, as the case may be, shall be recorded in the
log book at the end of each flight or as soon thereafter as is reasonably practicable,
including:
(a) the date, the places at which the holder embarked on and disembarked from the
aircraft and the time spent during the course of a flight when he was acting in
either capacity;
(b) the type and registration marks of the aircraft;
(c) the capacity in which the holder acted in flight;
(d) particulars of any special conditions under which the flight was conducted,
including night flying and instrument flying; and
(e) particulars of any test or examination undertaken whilst in flight.
Whereas there are definitions in LASORS concerning 'instrument flight', there is nothing which defines 'instrument flying' in the ANO unless I've missed it. Mind you, I would certainly agree that 'actual' and 'simulated' IF (as used in the RAF) is the only IF time which is worth logging; time merely under IFR is meaningless!
Incidentally, Miserlou, there is NO NEED to file an airborne flight plan in the UK to fly under IFR outside RAS - the ANO spells that out quite clearly.
This whole thing is a typical CAA/JAA botch up where the wording is different and misleading between JAR-FCL and the ANO. Just one of many instances of such!