Thanks for the informationI'm 5'10'' and had a 17'' Roberts White Spider, my heels kept clipping the rear brakes and it felt too small generally.
Of course some Roberts bikes were custom made for specific individuals with different requirements, and just as no two people are exactly the same, no two 17'' Roberts will be the same fit.
Looks like it was the 13th bike made in April 1996, no clues re the model in the frame numbers.