There is a whole section of the EH web site on SMRs
Go to http://www.english-heritage.org.uk
and then follow the trail: Resources & Galleries>
Specialist Services> Sites & Monuments Records (SMRs)
There is also more information on heritage data
standards (and links to useful information) if you
follow the trail from the EH home page:
Resources & Galleries> Specialist Services>
Developing Standards that leads to lots of stuff (and
links) relating to data standards.
There is also [log in to unmask] - mailing list all
about heritage data standards.
Good luck in your endeavours!