Agreed - but it wouldn't count towards any licence issue requirement which is what the CAA are stating.
The UK CAA has clearly stated it does not recognise two pilots simultaneously logging PIC time as in scenario 2 above.
Returning to the AMC (unmodified by CAP804):
... the holder of a pilot licence occupying a pilot seat as co-pilot may log all flight time as co-pilot flight time on an aircraft on which more than one pilot is required under ... the regulations under which the flight is conducted
Since US Part 91 regulations require more than one pilot during simulated instrument flight it seems reasonable that the safey pilot in scenario 1, being a required pilot, is entitled under EASA rules to log the appropriate flight portion as co-pilot time.
The EASA Aircrew Regulation requires candidates to have "completed 150 hours flight time" prior to commencing a modular course for the CPL(A) and to have completed 200 hours flight time before licence issuance. It appears the safety pilot in scenario 1 may count his co-pilot time towards those EASA licences and rating requiring some number of hours of "flight time."