Thanks for your quick replies and for the links.

The conversion charts are really useful.

As for the measurements I have, I found the same measurements in
several places, so took these as a guideline. I think these are
rounded up, because you don't want to be measuring "point something"
of an ounce! So these suited me and I wondered if there was anywhere
else I could find for other ingredients such as rice, raisins etc.

I have come to the conclusion that if you stick to the one conversion
chart for your recipe, it doesn't matter. As long as you don't mix
and match!

The cake was amazing by the way.
Joan