Either copy/paste the code below into notepad and save as "scan.xml" in your C:\Program Files\Mozilla Firefox\searchplugins directory, or download the zip file below and extract it to there instead
Code:
<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/">
<ShortName>scan.co.uk</ShortName>
<Description>scan.co.uk Search</Description>
<InputEncoding>ISO-8859-1</InputEncoding>
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<Url
type="text/html" method="GET"
template="http://www.scan.co.uk/Search.aspx?q={searchTerms}"/>
<SearchForm>http://www.scan.co.uk/</SearchForm>
</SearchPlugin>
or download here.
Preview:
Hope you like it!