I know of one guy who advertises with us ( www.sarnia4rent.com ), and my partner uses him for managing here in sarnia, but he is actually located out of London, so he may be a good fit for you. feel free to check him out, and if you want a review of his work PM or email me and I will get you in contact with my partner.
the managers contact info is:
Anthony Mota
301 Oxford St W London
519 457 0491