Found it... It's even shorter! marked 70. More like 75 c-to-c. Rather unusual in such a short length. I think I used this or an 80mm once. Makes for some quite 'responsive' feeling steering. Or maybe that was the forks! My plan had been to buy a scruffy cheap one for a bolt. Sometimes Hilary Stone has scruffy ones super cheap, £12 or £15. It is in pretty nice condition, but one scuff to the front top. Could polish it, or fine used as is. If you might be interested, let me know and I can take a couple of photos at the weekend.