Rockgran We had computers way back with the BBC Micro, so I acquired a certain familiarity with them. Then came an exciting addition - a handheld scanner that you could roll down the page and capture an image.
I bought one of these, attached it and found it did not work. What's more, with a bit of exploration and a vague memory of things DH had muttered about problems he had had with equipment at work,, I found out why it did not work -( its choices of IRQs was totally incompatable with the IRQs of the other bits that it was working with, if you really want to know)
So I took it back, and just said it would not work with my computer and I was returning it. Teenage expert took it into a back room to the boss, came back and said it worked perfectly with theirs, had I switched it on properly, and no, I could not get my money back, so I asked him about his IRQs.
He looked completely flummoxed, took it back into the back room again to ask his boss and returned with the money.
Non illegitimi corborundum.