I found the cheque stub when searching for the contract’s paperwork.
The date doesn’t just precede my credit history, it’s virtually pre- internet, and definitely pre- email & sms services [which I only began to use a year later]. On that last subject, I fondly recall the http://www.uboot.com/eng of 2001, who gave free unlimited sms-ing from the web to any mobile. Even @O2 allowed 600 web sms per month to UK mobiles. A decade on, and @O2 gives 10 sms as standard; which rather says much for how telecom pricing has evolved.