Reviews from various sites:
Trust Pilot (but these wanted just £100 a month just for using the review site I don't see how any small business could afford this).
Free Index seems to be great way to leave reviews very easy and get few books from this took my time creating the profile. http://www.mobilediscowirral.freeindex.co.uk/
Google review can be hard because the client has to have Google account and has to be signed in which cause make it hard for clients to leave stress free review.
Screenshot email reviews I have took also.