I'll be saving to floppy disk thankfully :) I've successfully got the checksum tool working now. Ironically the tool doesn't work on itself - I made several mistakes typing the numbers in which kept resulting in an out of data error!
I've ordered myself one of those magnifying rulers which will help me to both read what I need to type and keep track of where I'm up to (I'll be printing the listings out to work off).
Will be great to eventaully have another program that I can use my 1351 mouse with too!
Am I correct in thinking that I only need to type in the shorter v2.1 listing if I'm not bothered about joystick compatibility?