Haven't charged clients VAT for a year (stupid I know), but approaching VAT threshold

When I set up my business at the start of this year, I did so with haste (and now regret), and screwed a few things up from the start. One of these is the fact that I don’t currently charge my clients for VAT. I am aware that the threshold is £85k, but it looks as though I will exceed the threshold before the end of my accounting period, which I believe for my company is 28th Feb 2021.

Firstly, is VAT only paid on revenue over the £85k threshold (similar to how income tax works with bands) or is it paid on the entire revenue as soon as £85k is exceeded?

Is VAT paid at the end of the accounting year (every 28th of Feb if I am correct), and so you only have to pay VAT on revenue between 1st of March year prior and 28th of Feb?

As you can imagine, I’m not keen on losing 20% of my revenue, so I would like to avoid it if possible, at least on the revenue that I will take up until Feb 2021 if that’s possible… I have been thinking of ways to avoid passing the VAT threshold before Feb 2021 to avoid paying it, but obviously do not have the knowledge in order to know if these would work. I was thinking that I could perhaps ask my clients to pay me directly (into my personal account) and pay income tax on it instead? Or possibly ask them to delay paying the final few invoices until after Feb 2021 to stay below the threshold, then for any work after Feb 2021, charge them VAT on top.

Any help will be hugely appreciated!

Thanks for your time! 🙂