If you wish to increase your prices in bulk, either by a percentage, or by a fixed amount, and round them in the process, you can use the Copy Prices function

1. Go to Properties > Copy > Copy Prices.

2. Copy prices from a property to the same property, for the same year, but add an uplift with Price Rounding specified in the process. 

If you wish to display only full Pound Prices (i.e. £200.00) without pence, then make sure to select 'Round to 0 decimals'. 

i.e. If you wanted to uplift Cottage A for a single year by 5%, you would set this up as 

Full year,  Cottage A, 2020,  as the Source; Cottage A, 2020, Number of years 1 as the destination, with a 5% percent uplift rounded to 0 decimals.