@stell It seems to me the best way to achieve what you desire is to hire a managing director to sustain and grow the business while you retain a directorship and the shares. I assume the CEO salary will be at least $200k and up to $400k, netting you a $100-400k dividend plus any growth. Alternatively you could promote one of your existing team into a senior leadership position to take over the majority of your responsibilities and pay them an increased salary along with bonus or profit share.
As for the $700k - I would offset that against your mortgage while you have it sitting in cash and are deciding what to do. Then talk to your bank about their private wealth team. You may or may not have enough net wealth to be welcomed as a private wealth customer but you have enough income. I imagine they will consider it. They will be able to give you sound and free financial advice and you will get exclusive access to investment products.
I disagree with the advice here to speak with a general financial advisor. You'll recieve generic advice that is universally applied - as you have alluded to. The private wealth team with you bank will give you better advice and access to products and they'll do it for free (the advice part at least). Your investment fees will also reduce as you become a bigger fish.
Also I would always keep $200k in straight cash in your position while maintaining a $140k per annum lifestyle.