Why LAB, you are everywhere.
The G15 CSR was my first serious motorcycle and I confess to lusting after another some day, but they are so rare I've never even seen one.
I had mine in Maine and got it from a college chum. It was a couple of years old at the time and quite low mileage with red tank and Norton markings.
I flogged that poor beast unmercifully and it must have made over 50 quarter mile blasts on the original engine. It only lost one race and that was to a then new Honda 750.
Everything on that bike was tough, I was silly enough to ride it at high speed on dirt fire roads with clubman bars. Nothing around could keep up with it there, but as soon as I tried it in the off road parts all I did was get stuck and amuse my friends.
My missed shifts finally blew the rather tired engine after a few years, I was in college with no money and sold it to my everlasting regret.
I have a Commando engined featherbed now and I rode a Commando for many years so I have more to compare the handling to on that bike.
It was OK in high speed corners but if I recall the rear would want to come out. It would hop a bit first, and when it did you could back off and all would be well. My current featherbed on the other hand seems to be willing to drift both tires smoothly, which I never could do on that bike.
If it is geared as mine was it will probably be a ton of fun in the stoplight grand prix and might surprise a few newer bikes.