I have a Colchester Master, which looks identical to this one. Mine dates to 1967 and is in great mechanical condition. I think that the date is pretty close to what was stated in the ad.
It is imperative that you remove the head stock cover and turn the spindle by hand to inspect every single gear tooth. As well, remove the quick change gear box cover and do the same. Maybe a 10 minute job.
These lathes are extremely versatile, as they have both imperial and metric threading in one gear box. At least, I think yours does as well.