I understood you will still have the same number of shares. But there is now more of them. So your quantity is the same but your percentage is now lower.
So you own less of the company but ideally your shares are worth more individually.
You hold 488 shares from what you have said - the number of shares you own doesn’t change as the price increases - or - decreases - what changes is the value of that share - if you bought in the first round you would have paid around 51p / share , the last round the shares were priced at around 235p / share - the next crowdfunding round the price is rumoured to be around 771p per share
In other words you paid around £250 for your 488 shares and they will be worth around £3765 ( 488 x £7.71 ) if the share price is £7.71 in this next round
The only thing that changes is the value of your shares, never the quantity. You bought a set number of them, rather than investing a quantity of money.
On that point, I invested in Brewdog E4P IV in 2016, buying two shares
I now have twenty shares as they sub-divided them all in order to sell a large chunk of the private shares to an institutional investor and then a set of the “smaller” shares in E4P V
Search for Monzo Investment in your feed (mine was 5 Dec 2018) and the number of shares are shown when you look at the details. I’ve added #Shares to the Notes section to make it easier to find.