As I read George Dyson's excellent book (Darwin Among the Machines) it seems that this is only partly the full history. The rest of the fable concerns the information that the head would provide; a means to build a 'wall of brass' around England (yeah. Like that would work!).

Anyway, this mechanical head was also reported as the construct of Pope Silvester II - who 'helped introduce Arabic numerals and arithemetic into Europe' as well as making a 'steam-driven organ' and 'mechanical clocks'. Interestingly, for the conclusions drawn in the other writeup, the apprentice (Miles) took the piss most righteously with the head : "Do you tell us Copper-nose when TIME IS?" and "Thou Brazen-faced head, hath my master took all this pains about thee, and now dost thou requite him with two words : TIME IS?"

Clearly, the apprentice was messing around - let this be further warning. On a related note, there is a sentance in the chapter that is particularly apposite for E2:

"...the warning of the head goes unheeded as we stand transfixed, like monkeys given a mirror, by the novelty of our own image reflected in the surface of the web."