I have to agree with ppilot. Technical interpretation of the regs allows you to log PIC time as long as all those criteria are met.

However, in your case, UKman, I'd say you could not even technically log that PIC time because you are only type rated AS AN SIC on your certificate. Also, as everyone else has pointed out, it would be counterproductive to log those times as PIC if you're looking to get on with another company someday (and who isn't??), since they only want PIC time counted when YOU are the final authority for the flight.

Did you sign for the airplane?

If not it's SIC- if you want a job later in life...

Let me qualify JOB- one that pays more than you are making now...

They do say that Part 61.51 is a guide, but then they also add not to duplicate Dual in the the PIC, or any other column.

So If you have been logging dual given (as far as 61.51 allows you) as PIC time you are probably going to have to find that time and subtract that time from you total PIC time.

GL,