Glad you like it. For the premium of an extra £10 (ooooh!), taking it to £179.95 – probably quite a lot of money in 1980 – the main thing on the Special was Campag hubs (not sure which model), which are lovely, and still on it, though a friend has rebuilt the wheels for me with Mavic rims (still 27x1¼) to replace the original Weinmann (I think) ones. Funnily enough the cable loops were not on the original frame – I also had bands – but I snapped the frame round the bottom bracket pedalling home too hard one day a couple of years later, and the frame you see is the replacement under guarantee. I was pretty delighted to get the loops upgrade, though I remember they were a bit tight, and I possibly had to ream one or more of them out a bit to get my cable through without tearing the cover.
The frame is the same Tange no. 5 tubing as yours. The front and rear mechs are the original Shimano 600, although I changed the (Sugino? SR?) crankset and chainrings for Shimano 600 AX, which I found remaindered in Whiskers or somewhere, and which feature an oversize axle, based on the theory that all your weight is pushing on there, and a spindly spindle is maybe not so good. It was a short-lived development, though, I think, and of course unless I change the cranks I'm locked into using the AX pedals. The original brakes were Shimano Tourney, which I've replaced recently with Shimano RX100 BR-A550s The Brooks saddle is from my generous wheel-building friend, and the bars are the original Sakae Road Champion like yours. I've ditched the mudguards, which were Essgee, I think. Seatpost – probably the original – is SR LaPrade.
The only other thing I can possibly dredge up from my memory that made it the Special is that the lugs featured hand-painted gold lining. But I can't tell from your pic whether yours does too. Do you want to see detailed pics? I'm very happy to take some, but don't want to bore anyone.