It is interesting how the learner rider laws used to be. One of my earliest bikes (while still on L plates) was a BSA C11G at 250cc single cylinder. It had the old Jam Jar suspension on the back and could easily hit 65mph if you had a following wind and big sail on the back ..
I searched around online for a pix of one and came up with this .. phenomenally clean example.
Not a particularly elegant bike but a good old plodder for all that.