Pin Head - (from the notes at the front of my logbook) - Times should be recorded in Greenwich Mean Time (UTC) whenever possible, but if any other time is entered its relation to GMT/UTC should be clearly denoted by marking the particular entry as "summer time" or "zone Time".
Dent - In the ratings section of your licence you will see that you have an MEP (land) rating. Unless the rules have changed dramatically (which of course they may have) you are therefore licenced to act as Pilot in Command or Co-Pilot on Multi-Engine Piston aircraft <5,700kgs. Therefore, you can log the Chieftain time as P2/Co-Pilot.