Hi, this appears to be your first message so welcome to the BBS. Webley Hurricanes and Tempests are pretty much universally loved, because they are a nice simple design and feel and look good. They are also great for plinking, though for serious target shooting I don't think anyone would bother.
Back in the 70s and 80s the type of scope for this pistol would have been between 1x and 2x and most importantly an eyepiece which can be viewed at arms length rather than just a few inches, as is the case with rifle scopes. You may think what is the point in such a low magnification? The function of this scope is to provide you with cross hairs as an aiming site, not to magnify the image. Any more than 2x mag and the image dances around so much when held at arms length that it is impossible to aim.
Now adays, most people use a red dot sight (or use the open sights). A red dot sight is not the same as a laser, a red dot sight uses an LED and some very simple optics to superimpose a red dot on the target when viewed through the sight. The magnification is usually 1x (i.e none). I have only used a cheap one (GBP12.00) and it is great fun on a pistol. You can buy more expensive ones but I think a cheap one will be as accurate as your pistol.
From a practical point of view I would recomend either the existing open sights or a cheap red dot sight. If you want to be historically accurate I am sure you can find a pistol scope on an auction site or by putting an advert in the wanted section on this bbs.
Dave