ummmhmmm....I know exactly the parts counter guy your talking about, but since I am so close I use them for parts whenever I am in a time crunch....If you pick up the parts their prices are reasonable.
Now to the real question, a good shop.....Well there used to be British MGB spares in Milton, but the enchanted owner, Tommy, saddly passed away a few years ago...and although I do almost all of my own work his advice and friendship has been missed, along with his ability to 'certify' my cars /ubbthreads/images/graemlins/wink.gif ......I haven't been by the shop since his passing, but I heard his head mechanic(ie only mechanic) took over....Then I heard that everything was sold off, so I am not entirly sure of the situation.
Theres always Precision sportscars in Markham, I can't recall the owners name off hand....But he has a very nice Healey, just google 'precision sportscars' and you'll find his website...He's probably your best bet
There is a few smaller british 'shops' around here but most are run by 'club guys'(if your not in with the club your not in with them)outta their personal garages and such.
If your not really concerned with the place being a british only shop you can also give Kirk Robinson a call(Robinson Automotive) He the host of 'auto talk' a local cable TV show where people call in with their questions and used to work as pit crew chief for the Players Camaro racing team back in the late 80's(I originally started taking my Camaro to him as he knows those things like the back of his hand)...but now he works on all my cars, he's done my MGB clutch last year, complete brake job on a seized solid 73 Vette, and just repaired my TR6 diffy mounts a few weeks ago, plus many other regular jobs on the DD's. He an his son are very pleasant people to deal with and have become pretty good friends of mine...If you do go there tell him Ron sent ya, and he'll do whatever it takes to get the job done right.