Thanks Colin, that makes good sense and worked well

Two further things have cropped up, one from your reply, another from the time adjustment.

1) You mention for example using a single cell to reference to - considering the DST/BST etc time changes that makes sense. It worked for the first cell in the column, however if I used the little black cross symbol that pops up when you hover bottom-right of a cell to then replicate the formula down the next 195 cells in the column, (for example) (E1/24) then became (E2/24), (E3/24) and so on. Is there a cell format to change to stop that and to make each cell reference only E1 and not each consecutive E cell?

2) There is a column in the sheet with the Game dates in - labelled "START_DATE". Some of the games start at for example 7:05PM ET. Add 5 hours for my timezone and that becomes 12:05AM UTC. That is obviously into the next day, and so I was wondering is there a way to adjust the date (in a new column, as similar to the time adjustment) to change the date if the Start Time goes over 12AM?

Thanks again,

Karl