Hi Andy and welcome to the forum. Hopefully someone will come on and give you some more info but in the meantime I will tell you what I know.
I used fish it a bit for a few years, first day I ever fished there I had about half a dozen fin perfect rainbows of about 3/4 lb, the guy who runs the place Iain Muir reckoned they were breeding in the loch but im not so sure as never caught them again.
I never again caught 6 fish in a session there, in fact I have never blanked so often at any water as i have at Corby.
Some cracking browns are caught there every year, mainly from the boats which seem to be reserved for the members. I have spoken to a lot of members there over the years and everyone agrees that its a tough venue but that the fish are worth working for.
Its a deep water so warms up slowly, think they hardly bother fishing it til May. I believe a lot of the members fish it mainly at night for the best chance of a fish.
I have stayed there into darkness before and watched big trout cruising the shallows with their backs sticking out of the water. Never seen anyone actually catch one of these though so don't know if they are browns or some of the stocked rainbows.
If they allowed float tubing I would fish it again but was no chance last time I asked.
Edit to add I just did a search for Corby Loch using the search function at the top of the page and there have been loads of discussions before. Worth a look