Marking this more as feedback ATM because it’s potentially stupid…
Credits to the account are in green and shown with a plus + symbol
Is there any reason why debits aren’t shown with a minus - symbol (I could go as far as to say if the credit is highlighted in a colour why not the debit aswell but I can understand the use of red/danger colour could be alarming)
Maybe its just my OCD or ott sense of consistency so feel free to ignore 
As 95% of my transactions are money out I think it would look pretty horrible for them all to be in red. I much prefer having the occasional monies in standing out as different and the standard plain format for the rest.
Yes, I am tending to agree with you on it would pretty much look like a sea of red with a hint green for most Monzo customers I would have thought. Plus I think people understand the way it is now.
Ok ignore the colour… that was already flagged by me as a bad idea anyway, focus on the symbols 
Same thing, as Fergus said swapping it for - 
As 95% of my transactions are money out I think it would look pretty horrible for them all to have minus symbols next to them.