because one passage was over the other, I have had to load copies of the
image then drawn the scraps one on each one, if I could just hide a
scrap I could have just drawn them on the same image, then the joins and
everything would have been in the right place.

Yes it would have been easier if I had started a new file for each part,
but when exploring new cave sometimes you do not realise until it is too
late. I have lots of examples of this, picked an old one as it is one of
the clearest.