Silly Delivery allows you to set a preferred courier option - we do not
have EVRI, DHL or YODEL where we live so I have set the default to be
Royal Mail. Not sure how I found that screen, but I think it was when I
created a new item.

I have found my older listings have been unmauled, and left with
Sensible Delivery - but if you try to amend anything it will switch to
Silly Delivery and there is no way back

Thank you to those who advised some categories allow Sensible Delivery
for items under £20 - I have been through all my listing and changed
them where I can to one of those categories.