There is a plate with an a number stamped on it by the ignition key, and date of manufacturer on a little oval plate near the clutch pedal on the side of the gearbox. It has varied over the years though, bearing in mind the 35 was manufactured from 1956 to 1963. The other poster is right, fofh website will set you right.
When looking at insurance I recommend someone like walker midgely who will insure it for circa £40 per annum, as a vintage tractor, including agricultural use and public liability to go to your local show or ploughing match ! NFU are more like £200.
Cheers. Stu