Here is what CAP407 (CAA’s Personal Flying Logbook) says about the Instrument Flying column.
The column headed “instrument flying” is provided in order that flight time during which the holder manipulated the flying controls solely by reference to instruments, either under actual or properly simulated instrument flight conditions may be recorded. The time spent in practices in a ground trainer eg a procedural trainer or flight simulator should NOT be recorded under “instrument flying”, but should be entered in the appropriate pages at the end of the log book.
From this I would agree with Mr B and others that say you can only record time when you are Pilot Flying and in actual or simulated IMC