I am sure that the Tempest is probably classed as a newer model on here with the collectors but they were a nice looking gun.
Some of the real experts will be along to tell you what came first but I think Webley started with the MK1 pistol in about 1930.
Other models were the junior and senior pistols, and I think that the senior was replaced by the premier around 1960.
Mid 70's saw the Hurricane and less powerful typhoon introduced and made until the early 90's, and the more compact Tempest was introduced around 1979 and made until about 2005 according to the blue book but I believe that you can still buy the Tempest albeit a Turkish made one.There is also a new version of the Typhoon made with synthetic stock.
I know I have generalised and missed lots of Mark numbers and different variations along the way but hope this helps a bit.
If I have got some bits wrong someone more knowledgeable will correct me.