Ok, I'll assume you're in the UK Wolverhampton, so that leaves us with a couple of scenarios;
If you've not flown the Warrior before, but have a current and valid medical, licence and SEP(L) class rating. You're going up with an instructor to learn the specifics of a Warrior, compared to what you've flown before. You could probably legally be PIC, but common practice, club rules and insurance mean you are having a check-out. I would say you would almost always log this as PU/T and the instructor as PIC.
You have previous experience on the Warrior, have a current and valid medical, licence and SEP(L) class rating. You have however not flown sufficiently or recently enough to meet club or insurance requirements. This one is a bit more debatable, however in a flying club environment, typically expect to log it as PU/T and the instructor log it as PIC. Personally I do sometimes let the "checkee" log these flights as PIC, if I do nothing other than observe they are still safe and competent, if I intervene at all the it's PU/T. For this to happen they have to have the 3 landings in previous 90 days of course, so I can be a passenger rather than an instructor.