That is because Google will return what they think your customers are looking for and based on the most popular searches, London England will be returned.
There are various ways to work around this.
1) With the base SLP and no add-ons Add text in the search form box (under settings/Search/labels…that will assist the user, such as enter city and zip or city and country. Consider this label as a help text tool for the site visitor to assist them as to what will return the fastest results. Label Examples: zipcode, city, street, or a combination such as address / zipcode. The more detailed the better. We find address and zip code to be the most useful hint. If you leave this label blank nothing will appear in front of the search form box and your site visitors will be guessing what to enter as keywords to search (the same as any other search boxes). They can type in anything an hope that Google returns what they are looking for.
2) Add-ons that can allow discrete searches, or add a drop down of where your locations are for example, or autocomplete or show Google guesses etc. (see what to buy)
3) if all your locations are in Canada, you can also use the Append to search setting available with the experience add-on.
Please follow the posting guidelines and provide your plugin environment. Since I do not know if you already have add-0ns, what versions, or if your site is https, I have included as much information as possible as to why the results are going to London England as well as methods to assist your users to obtain best results.
If your site is HTTPS and you believe all your users want locations near them you can use location sensor.
Documentation on how the search, Google API, and add-ons work.