Here PhD (or DPhil, as we call them in Oxford) applications are centralised, both for generic and project-specific positions. If you are interested in working with me, you should apply to the Particle Theory programme (see here for details, be careful about deadlines) and select me as a potential supervisor. Usually deadlines for funded/unfunded positions are early January/early March. Successful candidates are expected to start their programme the next fall, and will also be guaranteed a college affiliation.
Unfortunately, we do not hire PhDs out-of-cycle, nor are able to consider any application that does not come from the route highlighted above.