If you’re going for a paid resource then I recommend Medify. I did the UCAT this year (I’ve posted some tips and my experience on my journey journal further back and on the UCAT experiences thread) and purchased several resources, none as good as Medify. I would steer away from Australian companies since UCAT was only recently introduced, Medify has collated their question bank over many years and has the best one in my opinion. However, don’t feel pressured to buy paid resources, there are some great free ones and the ones you should be using the most are the official question banks and mock exams from the UCAT website. I really don’t think tutoring is necessary. Most people who did well that I know of didn’t do tutoring. UCAT is based on your practice, and the more you do the better you’ll get, tutors won’t help with much for this unless you find yourself struggling and might need one or two lessons to get you on track or something. Unlikely you’d find yourself in that situation, anyhow, there are some great youtube videos and websites that talk about different strategies that can help you develop your own.
All the best!
EDIT: fixed some typos