Always refer to the guidance published by your educational establishment.

In the absence of advice the site authors suggest the following method:

Author or editor, year of publication, title, [Internet] KAS, Maidstone, Kent, England, <http://kentarchaeology.ac/(rest of URL)  [Accessed (date)]

example:

within the text [Ashbee (2002) pp. 3 - 4]

endpage citation
Ashbee, P.,  2002, Great Tottington's Sarson Stones, [Internet] K.A.S., Maidstone, Kent, England <http://www.kentarchaeology.ac> [Accessed 1st June 2008]
Some establishments prefer the full URL.