Your TCOS requires you to complete the SITP for your branch, then complete 30 months Return of Service - after which you can submit 12 months notice to quit. You can quit after serving 4 weeks, up to week 26, after which the RoS applies. In other words, if you don't quit within six months, you must complete the minimum term.
The SITP is listed in BR3 in the reference library on the RN website - it's on the eligibility matrix.
What don't you like about the job, as a matter of interest? Is it related to lack of sea time or the arrival of a frontline seagoing draft?