Re: Software via teletext...
When I was 15 I applied for funding to buy one of them and a BBC plus a specific model of video recorder that was easy to hack. The idea / purpose? To code a method of setting a VCR programmer using Ceefax/Teltext program listings and adjust the start and stop times automatically if the program start was delayed by say an over-running sporting event. I had a rudimentary 6502 machine code program already written to handle the user interface and control the tape transport system - I just needed real teletext data, a BBC to work on at home instead of writing it all at school during lunchtimes and a VCR with full solenoid control instead of just a prototyping board stuffed with optoisolators and LEDs.
Funding request was rejected but two years later the first PDC VCRs were launched followed shortly after by VideoPlus+ program code machines. Im not sure if this was connected or not!