I was wondering if many PhD become available for a January start,are these unusual?

You can start a PhD at any time of year, but most funding becomes available in October and so that's when most PhDs start. A few projects do get advertised for a January start and there are always a few October places unfilled (due to people pulling out or not getting the right grades), where a later start is possible. There's no harm in keeping your eye out for these.