We had the worst experience with Somerville and would not recommend them to anyone. I actually complained to the Better Business Bureau about this company when they failed to fix my leaky shower head; however, I've just discovered Somerville still defiantly displays a BBB rating of A+ on their site. My complain to the BBB is documented here: https://www.bbb.org/mbc/business-reviews/plumbers/sommerville-and-son-plumbing-and-heating-ltd-in-port-coquitlam-bc-197204/reviews-and-complaints
The reason I was looking at this again, when the original complaint was made in March 2016, is because recently we finally got tired of listening to the shower head drip, and called someone else to fix it. This second plumber came and did EXACTLY the same job as Somerville - he replaced the cartridge. But this time, he really fixed it.
So either Somerville did a shoddy job, or the cartridge they inserted was defective. Whatever the reason was, it cost us $300-plus dollars and our leaky shower head did not get fixed.
Thank goodness we didn't listen to Somerville's manager, who told us over the phone, without having seen the shower head, that the only fix was now to cut into the tile (!) and remove the whole shower head apparatus. I can't imagine how much that would have cost if we'd taken his advice. As it is, we're out $300+ dollars that we paid Somerville to fix our leak, which they failed to do.