No need to do anything actually. Unless i am missing something on what you are trying to achieve you could simply use {Actual Deal Value}*0.35
Andif you add sum in the bottom of the columns you can set the £ there and it shows for every row. No need to add it manually with formulas and you can totally actualy use the numbers as currency
Currently unfortunately although obvious currency doesn’t show 2 decimals if the last ones are zeros which very frustrating. There is another formula that overcomplicates things for that. Here it uses the formula to also subtitute . and , for us Europeans but should be the same principle. I would keep it simple though only by using the formula and adding the sum.