i remember either sinclair user or your sinclair having a feature about how the 48k speccy had the same insides as the 128k speccy and all the diffince was is a small program to tell it to run in 128k mode..
it had a program printed on the page that you could manualy type in and change the 48 speccy to 128...
i sat there with my girlfriend typen in the code and we where both excited checking every line of code before pressing enter..
when i did the screen turned black then white and april fool scrowled up the screen.....
they got us good.....lol