Not an Enfield, but I sold an '09 Kawasaki EX500 about a year and a half ago for the same reason. I had one back in '88, and had no problems with it. I guess I should have realized I was more than 20 years older. '09 was the last year of production, and the bikes were not selling well. Local dealer had just gotten a truckload of them, and was having a fire sale. I couldn't resist the price, and jumped at it. It felt pretty good on the showroom floor. I realized I had made a mistake by the time I got it home, and was hurting all over. I kept it 3 years, even put bar risers on it, but still had less than 5000 miles on it in that time, most of them in pain. So it had to go.
I have put over 2000 miles on my B5 in less than 2 months, and have had no problems, other than the seat is a bit hard. Not a really big deal, it starts to get uncomfortable about the time I need to get gas.
Most people claim the EX500 has a "standard" riding position. Not even close. It's not a supersport, but far from being a standard. I consider the B5 to be a standard. It has a far more upright riding position than an EX.
Again, if they would make a GT with a standard riding position, I would probably be interested. It's a beautiful bike, ruined for me by an impossible riding position.