I certainly did. I took the chance on it and facilitated a city break in Lincoln with my partner to pick it up!
The frame is a little ropey but I think I will just treat the rust patches and wax it, so its still original. It is cleaning up nicely and I have some Super Record brakes to go on it. The chrome isn't too bad and the crumpled cooking foil technique has brought it up beautifully. The wheels are not original but I will keep them as they are.
It has "brev Campagnolo" dropouts which date it to probably 1978/79. My dealer price lists show the last time it was included on a price list was November 1979, so it seems quite a late one.
I would say you are probably about right for the date of the bike, as the seller did send me some detailed pictures when it was up for sale. You can probably get a date code off the Gran Sport chainset?
Interestingly the chrome seems to extend a long way along the top tube under the paint?
Good idea to keep it as original as possible.
I have publications that show the 76 for for sale in 80, 82 and 83. Also an early eighties brochure picture of one. How difficult they would have been to get is another matter lol