I have been doing this manually but I'm sure there must be a way of doing it
automatically:
on a sheet with cells containing a school form reference (eg '7A') with an
abbreviation for 1) subject 2) teacher and 3) room (all three in separate
columns!)

I would like to be able to (automatically!) look up and read the cells that
contain say '7A' and concatenate the three strings into one cell.

Later I can remove the extra occurrences of the form ID (eg '7A')

I hope this is clear enough
Thank you