Morris Minor Owners Club

Is there somewhere which sets out the steps to be taken to change from positive to negative earth?

any help pointing in the right direction appreciated

If you click on the 'technical tips' link to the left of this page details are shown under 'negative earth'

An important point if you turn the battery round, is to make sure the non-earth terminal (ie +ve after the change) is well away from the battery clamp and securely held so there is no chance of the terminal ever touching the clamp.
Edit - Oh dear - just read the 'Tech Tips' - never noticed them before.... You also need to clean and re-gap the dizzy points because the peak and pit in the contacts will now reverse. Same with the fuel pump - clean the contacts. No mention either of the early silver/gold fuel gauge where the connections on the back will need to be reversed. The black gauge is fine as it is - it's a 'hot wire' gauge and doesn't care which way the current flows. The wiper motor does NOT run backwards (which is why it has never given any problems....) - it has both field coils and armature coils - the current in both is reversed, so the motor continues to run same way as it did before........