The page_header macro includes an optional back link. Since the
page_header is always used inside `<main>`, where the back link should
not be, this stops setting the back link in the page header and instead
sets it in the new `backLink` block.
Add more spacing between characters for billing reference number and PO number, so they are easier to read.
Also remove unnecessary autofocus.
Co-authored-by: Chris Hill-Scott <me@quis.cc>
As per ticket and as per Caley's request, so everything can be
edited together.
Also pluralise labels for billing contact info, to indicate
that putting multiple in is ok, and widen the input fields so
that it is more comfortable to input multiple contact details.
