Just come into this thread late, but might be worth adding, Mort, that although most movements would have had tempo indications in Handel's time, there's nothing particularly significant in his decision not to give one for this particular movement - he probably just thought it was obvious. It's not as if it would have said 'Without tempo indication' in the original score! It was just blank.

It's only the modern invention of CD track listings and the general convention of using tempo markings as track titles that draws attention to movements without tempo markings.

In other words, it's all our fault, not Handel's!