You have such a specific scheme that I think you need to look at the fine detail.
I’m guessing you joined in 2007, and have 9 years in the 2006 scheme and 6 in the 2015 scheme?
Leaving the 2015 scheme won’t have an impact on what you get from it. It’s care average and based on what your actual salary was in each year - updated by CPI + 1.25% (don’t take that as gospel!). So whether you leave tomorrow or in 10 years, you’ll still get the same pension for what you earned in “2022” for example.
What you might miss out on is a good pension scheme going forward - but no-one can tell you about that, it’s new job dependent. You could get a higher salary in another care scheme. If you get any public sector job, your pension could be similar.
The issue is your 2006 scheme. Again, it’s your pension not mine, so don’t take this as gospel! Do I understand correctly that your “final salary” for the 2006 portion is not your salary in 2014, but your salary on leaving? So at the moment, your current salary. If you don’t expect any further salary progression in the police above current + CPI, then it makes no difference if you leave. But you’re very unlikely to find a final salary scheme anywhere now, so if you could have stayed and been promoted then you very likely will lose out in pure £ terms.
Life is too short to stay where you’re unhappy and with 15 years police pension you have an amazing guaranteed pension to be able to take some risks. But with 9 years accrual in a final salary scheme that still looks at your current salary… I would maximise the shit out of increasing your salary before you leave. Not to the detriment of your health, but sticking out a promotion you don’t really want long enough for it to count as your final salary could be an excellent strategic move!