How can I do this as all I get is the AmigaDOS SETPATCH: wrong number of arguments and when I type in ed s:startup-sequence and delete the line I added and click on top left nothing happens and I have turn the Amiga off and rebooted and the same screen comes back?


?
I don't understand what you mean by "click on top left".
To save the file after edit you just type "[escape key] x".
The format for adding chip ram in that line btw, is:
C:SetPatch QUIET ADDCHIPRAM=[number]
#6