One way hash of data records (PBKDF2?) I'm looking for a way of one way hash data for multiple records. We have a privacy requirement to anonymise information "after it's used for its intended purpose" which is a little wooly at best.

I'd therefore like to delete everything once a project is finished, but this has been met with pushback internally "in case clients as follow up questions", so I figure the next best way is to hash the data with a one way system, so, it's effectively anonymized, not even we'd know what it was, but, if supplied with an email address (for instance) to lookup, we could hash it and search for a match in our database.

I'd need something that non-technical users could use and wouldn't be overly onerous in time, as it's an uphill battle to get people compliant already.

Hoping for an excel solution, or something that could load an excel/csv in and spit out the hashed version, however everything I look at for PBKDF2 is for implementing in websites or similar, singular password use.

I managed to get SHA256 working in excel, but as there's no salt they can be reversed with some work, meaning our effort to make the data anonymised is disingenuous, which is where i came across PBKDF2.

As you can tell be reading this far, I'm a bit out of my depth and would like to appeal to those who know more than I for any help!
Even with PBKDF2, You wouldn't be able to use salt anyways, because salting relies on a one-to-one mapping between the salt and a user identifier (email). You cannot keep the email, so you wouldn't know which salt to use when a user comes back with his email. 

Simply iterating SHA 256 for a large number of times is a way to discourage preimage searching. Other (more solid) cost-incurring algorithms include scrypt. Although time-space balance attacks still work if you don't have salt to work with. (Using SHA, possibly inserting large constant data after input string to further slow it down).