The answer to the issue was indeed a vlookup. Being an Excel novice, I'd never had cause to investigate or use this before.
The dull problem was that I had a full master customer list containing email address, name and a unique ID. I had another smaller list of just unique IDs of customers who...
Morning NSC,
If there are any Excel experts around, I'd be grateful if you could drop me a PM as I've got something I need to achieve outside of my knowledge!
Cheers in advance!