I got an incredible deal through
https://www.autoeurope.ca. It was ~$450 for ~3 weeks.
I will say it did not go 100% smoothly, but that is becuase Europcar was staffed by morons, and our 3 hour delay mucked stuff up. Be prepared for a long wait at Glasgow, no matter who you rent from. All the companies had lots of customers waiting for eternity. If you go Europcar there is a non-obvious screen to enter your info which gets you a place in line. If you can pre-register ahead of time, I highly recommend doing that, but their site didn't work for us.
If you want to use your credit card insurance, make sure you have a print out, or it saved on your phone. The moron would not let me decline it until he saw proof I had coverage, which meant running back to the main terminal to get wifi and downloading it.
Maybe look at a Skoda wagon for a rental. We had a Fusion but I'm not sure you could get 2 golf bags in.