I have never measured it, but I will tomorrow.
I have always thought it was 17.5 as that's what I was told.
My guess based on your info would be 16" Im 5'8 and that's set up for me.
Supplied by BikeTech Cheltenham and built by "The Guv'nor", himself back in 98 / 99.
Less than 1500 miles from new
17.5" Frame
Full LX 27spd groupset
Kore Bars and stem
Rockshox SID forks
No pedals
Back rim was smashed up by someone trying to nick the bike a few years back, so its got a...
Spooky!
Funny, my first 'proper' mountain bike ride was that identical one, yet in reverse.
Strangely enough 20 years ago also!
Raleigh Cobra, 15spd, non SIS.
Plenty of pushing from the bottom of Daisy Bank, right the way upto the bomb hole!
:D