Is this a tree sparrow?

I live in the Outer Hebrides.  Last year, tree sparrows were spotted on Lewis for the first time in 25 years (http://www.stornowaygazette.co.uk/news/local-headlines/tree_sparrows_breed_on_western_isles_for_the_first_time_in_25_years_1_1766792).  I saw this bird in my garden yesterday.  It looked different from the other sparrows so I was wondering whether it might be a tree sparrow?  I live over 20 miles from where the tree sparrows were sighted and am on the coast rather than surrounded by woodland. 

Your help as always is appreciated thanks.