You can leave the column in place just make sure the steering wheel is off.
Also it is easier if you have the dash loom already attached to the dash when you put it back in place and then reconnect it once in. Amd maybe use some masking tape arounf cables and write on them so you know wht goes where for when you put it back.
Becareful with the 3 x top fixing on the dash as they are prone to breaking when put back in and the same for the side 1's (I still need to replace 1 of mine after breaking 1).
Column still in place (My new dash I put in)

How it looked once finished (before i gave it a clean)

Can't emphasis this enough just take your time matey.