I do work for a property management company who sub it off a large nation company, I offer a 1st cleass service and I price accordingly.
The company who I work for now understand that if they want a 2st class service, then the price will reflect this, the company they sub contract work from still want the best deal possible, which I cannot say is wrong, because we all do it. Why pay £1200 for van insurance when you can get it for £788, I know this, because this happened, this year with my insurance renewel.
I have also turned down work by some nationals, when they want me to work for half the money I am already achieving, asking for window cleaners to refuse work to force the nationals from going after this work will not work, all they will do is add the cleaning of the windows to the duties of the general cleaners they already have on site, and get away with paying the minimum wage for the job.
What I have found works best is to get the customer to be vocal to the nationals, complain on a daily basis and create as much hassle as possible for them, they don't like this and then they either pay more for a better clean or increase the cleaining cycle.
You can also buy some shares in the likes of Tescos and at their next AGM you can go and vent your spleen against the CEO, but will you win back more business for the local guy???