After trying to things in Thunderbird or other email applications, I realise it isn't really suited for the job.
What I'm after is a simple contact management system which my father can use for his business. It could be either installed on a local PC, or it could be an online web based version (we have many apps available through cpanel on our hosting website, and can add SQL databases, etc)
Something like Act! could potentially do the job, a simple database where we can put in people's contact details, plus ancillary data such as classes they go to, what they've purchased, booked, etc.
Also, if it had the ability to do mailing lists (up to about 300 people), that would be fantastic.
Currently, I've toyed with the idea of using phplist as a mailer that could work, but coming up short on the contact side.
So, any suggestions? Key points are free / cheap and easy to learn, use and customise.