Yes, I thought it looked like a lot of code too!

I like the verification idea, but unfortunately the data being checked won't
always fit neatly into three strings with the number in the middle -
sometimes there could be as many as 5 substrings in a cell  with the account
number reference at any position (the data examples I gave were simplified).
Also, an added verification step may not be necessary in this case, because
each account number will be checked on our inhouse system to ensure it is a
valid account number. But I'll play around with it today and see if I can
integrate something like that.