Accountancy Firm Owner, Struggling with SEO

Hi guys, so i run an accountancy practice in the UK and have been trying with SEO for years yet to no success. I have 90+ 5 star reviews on my google page which help, but I know im not getting the reach that I need. Question is, i have spoken with many people who promise the world and those who want to tie me in for a 6months contract. I don't have a huge purse so I just don't want to be throwing money down a well. Any recommendations from anyone? or any people in this forum who help businesses like my industry?