Simple (hopefully) GDPR question

[sunbeam alpine]

My company only holds customer (and probably some lapsed customer) records on a single P.C. (we do have a data back-up!). This is purely used for invoicing purposes. We don't hold e-mail addresses - it's a local agricultural contracting business - and we don't do any marketing by e-mail or direct mail. We probably only have telephone numbers for about 50% of the customers on the computer (although they're all in my phone).

Do I actually need to do anything with regard to GDPR?

[sunbeam alpine]

Thanks for that.

Does it make a difference that the data held concerns businesses rather than private individuals?