Lew, by "Standon Springs" do you mean
Standen's, which is primarily a spring shop? Fred, I'm guessing this is who you are referring to, as well. They supplied the original equipment
axle (in 1979) for my
Boler, and were quite helpful when I had a question about it. I was not aware that they dealt with hitches, but I expect - given their suspension experience - that they're quite capable in that area.
My Toyota dealer installed my hitch, only because it was a Toyota option, purchased with the van. They send out installation of aftermarket hitches to a hitch shop, so in the case of this particular dealer, there would be no point in going to them now.
When I did my comparison shopping (in Edmonton, not Calgary), I found very little difference in price between dealers, and any hitch shop will do installations; the quoted prices normally
included installation. Since hitch installation is now an easy bolt-on, if I were doing only the hitch I would choose the hitch brand and model, and get it from wherever was cheap and easy to deal with.
Wiring is another matter entirely... so since that's needed as well, I would concentrate on that aspect. Unfortunately, I have no idea who is good for wiring, and I did mine myself.