Honestly, Bella Banquets is so-so… I wasn’t impressed with the interior or the exterior. I think hubby and I both felt it was a bit too rustic for us and I wasn’t feeling the round room. Plus they have these really steep stairs going up- so if you have older guests, its not ideal.
Kortright was the first place we checked out but their indoor area is on the small side- in particular their gazebo. We really wanted to be as outdoors as possible so we didn’t even consider their room - its all wood panelling and a gift shop so again, we weren’t that impressed. On the plus side, they have a gorgeous area for outdoor ceremonies and pictures. They allow tents to be put up but it was proving way too $$ since tent companies charge per person for the tent and then you pay for catering on top of that.
You’re right, Parkwood doesn’t allow outside catering but their chefs did a great job planning the menu with us to fit the Pakistani-European thing we had going on lol. And let me tell you, in all honesty, their chefs made SUCH good steaks that to this day, everyone remembers them. And I mean, everyone. Even our photographers were reminiscing about them when I met up with them the other day and they were saying everyone always asks about our venue when they see their 'folio. Its really beautiful and they have parking on site and in the school across the street.
I would seriously consider their BBQ option for sure. I think we were at about $60-$70 per head, including the tent rentals/chairs/tables/cutlery/glassware, etc. and the food and taxes.
Our menu was a live bbq with chefs grilling made-to-order steak, we had oh gosh, I can’t remember its an Italian dish- basically a spicy chicken and veggie saalan- we also had naan and other breads, eggplant ratatouille, Yorkshire pudding to go with the steaks, and a couple of other main dishes too that I can’t remember now. We gave them the name of our halal butcher and they bought everything from there and everything they prepared was delicious and well-made. And I’m quoting our guests here- sadly, I ate very little. But if it helps, a couple of people would have been pretty honest if they hadn’t liked the food but they had only good things to say too.
We had a plated summer berry salad to start with- this I did have and it was goood- and then the buffet with the BBQ and the rest. The cost also included a huge dessert table- basically 1 dessert per ten guests so we had 10 different kinds of cakes and pies and tarts and it was a huge hit.
The actual venue fee was $1400, if I remember correctly, and that also included our ceremony in the Sunken Garden. Now I got married in August 2007, so its probably gone up since then, but definitely if you can, pay a visit. You’ll love it! 
Oh and book before July 1st before the HST kicks in- it might give you some negotiating leverage in NOT paying the additional 8% tax grrrr so mad about that!