Columns for splits

Please can someone tell me how to move or delete columns when I view the splits on a ride?

First, you need to validate the implicit assumption that it is possible. From your choice of words, if doesn't seem to me you're starting from the position that it may not be possible for you to customise the presentation of data, but in case it is possible you'd like to know how.

So that it only displays the stats I am interested in?

I think we understand why you'd want it, but that doesn't mean Garmin Connect ought to be a customisable tailored information service or assumed to be one.