I was on Cix for several years. I can't remember what my username was. They had a really rather good mail and new client. A lot of the users were tech journalists and (oddly) airplane pilots. I originally connected using an acoustic coupler that ran at 9,600 baud.
I later migrated to Demon, which was originally formed by members of the Cix "tenner-a-month club" - a group that banded together to get real internet, instead of using Cix's curated internet gateways. Demon was a great ISP, until they were taken over by Scottish Power.
I'm an ex-demonite too. Had all the telehone numbers of the local pops (point of presence) in a file to copy to the moden after the ADT command. As the pops were heavily subscribed and would often just give engaged tones, I used to use the net at 6am. The phone rates were cheaper then too.
I'm a bit older than you and it passed me by along with CompuServe and other BBSs. It was mentioned in magazines such as PC Pro but I didn't get a modem until Windows 95 came out. After a quick play with the Microsoft Network the web took over for me.